The easiest way to create your own chest types is to download the example content pack from the files section of this mod and edit it as you like.

First, you need to change the metadata in the manifest.json file to suit your content pack.

Next, change the entries in content.json to fit your custom types.

Finally, you'll need to add image files to the mod for each of your custom chest type.

Here is a brief explanation of the entry data in content.json:

• chestTypes - the array of chest type objects
  
• name: the chest's display name
• capacity: how many items it can hold
• texturePath: the path within your content pack to the chest's texture. If you are using opening animations, use {frame} where the frame number will go for each texture
• frames: how many frames an opening animation will have (set to 1 if there is no animation)
• openSound: the vanilla sound to play on opening (default is "openChest")
• boundingBox: defines which part of the container should prevent movement. Values are based on the texture file. X and Y are where the bounding box starts in the texture file.
• description: the chest's description.