Needed:
Skyrim LE (certain circumstances)
Skyrim SE
Skyrim Creation Kit (32 bit) - Certain Circumstances
Skyrim Creation Kit (64 bit)
Nif Optimizer for SSE v2.5
BSA extracter tool
SSEedit
tes5edit
Nifskope

Step A: If the mod requires High Heels Esm and you are not using the Chinese Version for SSE, go to step A1, otherwise skip to step 1 (This procedure applies to any mod dependancy, mostly)

Step A1: Load the mod in skyrim LE (oldrim)

Step A2: Run tes5edit and go to spells - Right click to remove the hdt hh spell (might be called something else but the trigger will always be hh or hdt in the spell section}

Step A3: Find the armor (usually the boots or shoes) that has the vmad entry and delete (remove) the vmad entry (not the armor, just the vmad entry)

Step A4: Click on top level directory of the esp in tes5edit and right click.  Select clean Masters and then save the esp.  Your plugin should be free of the HH esm at this point - Check to make sure.

Step A5: Utilize the oldrim ESP (now free of dependancy) into your normal porting procedure (step 1)

Step 1: download the install file of the mod manually to a non game directory

Step 2: using Vortex or your mod manager of choice, install the file manually into your sse profile (install from file).

Step 3: close Vortex or other mod manager (don't run game yet) and navigate to the creation kit exe file. If you have already downloaded the creation kit from Bethesda it should be in your main skyrim se directory. Double click the creation kit exe file to open the creation kit. You Might get some warning but don't worry that's normal, just click yes to all when that happens.

Step 4: once the creation kit (64 bit - if it says 32 bit, then you need to get the 64 bit version) is open, click the load button (the yellow folder icon). This will open a window showing all of your installed esp files. Find the esp for the mod you are converting and double click it. This will put an x in the little box next to it. Now click on the button that says make active. Hit ok to load the esp. again you will get a bunch of error warnings but don't worry just say yes to all.

Step 5: now that the esp is loaded click the save button (the floppy disk icon) and say yes or close to any errors messages - this is normal. Once you've hit ok and saved, you can exit the creation kit, you won't need it anymore.

Step 6: now navigate to your sse data folder and locate your esp that you just converted and copy it to a non game folder

Step 7: go back into Vortex or your mod manager of choice and completely uninstall the mod from sse profile just like you would any other mod. The whole purpose of all the steps up till now is to convert the esp to sse format (form44).

Step 8: now go to the non game folder where you downloaded the mod install file and extract using 7zip (I use the option to extract to a folder with same name as the install zip, but you don't have to). Next, replace the old esp from the extracted files with the one you just converted.

Step 9: if the extracted files are all loose files, great. If not you will need a bsa extractor tool like Bethesda Archive Extractor to do it since sse can't read bsa from oldrim mods. Once all the files are in loose format, download a tool called sse nif optimizer and extract it into another non game folder. Does not matter where. Next we are going to fix the meshes to work nice with sse.

Step 10a: double click the sse nif optimizer exe to start the tool. For this first part we are going to fix only the face gen meshes so in options click on include subdirectories and head parts only. It is very important to only use headparts option for the facegen nif. Use the file locator at the top and navigate to the loose files folder where the facegen meshes are (data/meshes/actors/character/facegen) and highlight the facegen folder. Click on ok to run the tool. Once it's done, close the tool and read the txt file generated if you want to see what changes it made.

Step 10b: Next open the optimizer again and BE SURE to uncheck the head parts only box. Now run the nif optimizer tool on the rest of the meshes (But dont run it in the facegen folder). Ps, I recommend you use this optimizer away from the main games directory so you don't inadvertently screw up your other game files. Plus you need to be in a different directory anyway for the last steps. Again be very certain to uncheck the head parts only box for this step. Ok once that is completed you can exit the optimizer tool.

Step 11: now if you have any animation files you will need to convert them as well, when you downloaded and installed the creation kit it also downloaded a havoc converter exe into the tools folder in your main sse game folder. Copy this exe file into the loose files folder from before where your animation files are. You can use windows console command following the readme or if you are lazy like me just download a bat file to do it. There's one on the sse nexus. Once you have both those files in the proper animation directory just double click the bat file and it will convert them into sse format. You can then delete the havoc exe and the bat file if you want. I included the files for your convenience in the download

Step 12: Sometimes SSE nif optimizer will mess up the eyes of followers so if you have followers in the mod you are converting, open up the mod's facegen nif and a copy of the eyesfemale.nif from the Skyrim SE bsa in nifskope (I included one in the download for easy access). Here is how it was explained to me by ousnius:
 
 Note - Make a backup of the mods facegen mesh. Do not close the instance of nifskope with the source eyesfemale.nif.  The copied info is not stored in the clipboard, so the   source instance of nifskope needs to remain open until you are finished.
 12a - Load a working eyesfemale.nif into nifskope
 12b - locate 5-NiSkinPartition and highlight it (5 is the correct index for a vanilla SE eyesfemale.nif)  Hint - click the eye mesh in render view to highlight the correct   BSTriShape - BSTrishape > NiSkinInstance > 5 NiSkinPartition
 12c - right click 5-NiSkinPartition and select Block > Copy
 12d - Load the faceGeom mesh of the mod you are converting into another instance of nifskope (remember to keep the eyesfemale.nif open)
 12e - click on the dodgy eye mesh (not the head mesh itself) in the render view (this will select it's parent BSTriShape) and locate it's NiSkinPartion by expanding the branches   BSTriShape > NiSkinInstance > NiSkinPartition
 12f - Highlight the NiSkinPartition, right click and choose Block > Paste Over (not Paste)
 12g - Save the mesh and all should be good now.

Step 13: now that all of your loose files are ready for sse use 7zip tool to compress them back to an archive that Vortex or other mod manager will be able to use. I usually keep the original name with convertedtosse at the end so I can tell which one is for sse only, but its your choice what to name it.

Step 14: open up Vortex or other mod manager and and load your converted mod like any other mod. That's it, enjoy.

Addendum 1: Some follower mods include skeleton.nif or femaleskeleton.nif and sometimes they will not convert properly - if you get ctd after converting a mod with these files, you can sometimes delete them.  If not, then do not convert the mesh to SE - leave it as is.  Also you can change the skeleton to use your default skeleton using SSEedit

Addendum 2: Be sure to test all texture files using the latest Nif Optimizer by ousnius - most ctd is from bad textures or missing files

Addendum 3: Some mods will have dirty edits so it's a good idea to run sseedit after converting to clean them up.  Run SSEedit and select filter for cleaning and then select remove identcal to masters records.

If you have other issues, contact me and i will fix them if I can.