Here's the 411:
1. Install Reshade onto C:\Program Files (x86)\Steam\steamapps\common\Halo The Master Chief Collection\MCC\Binaries\Win64\MCC-Win64-Shipping.exe. Make sure you include the standard/default effects when asked.
2. Copy my .ini file to the same folder.
3. Start the game up, and once ReShade has finished loading, hit the Home key.
4. There's a little drop-down menu at the top next to a couple of arrows that will likely say ReShade.ini. Click it, and select my .ini file.

Thanks, and have fun.