To install:

Subscribe to the following (or use the MercTechV2 collection subscribe to all)

MW5Compatibility
MW5CAB
Mech_Bundle
MercTechComp
MercTechV2
Cockpit_Glass

If the game crashes when you start up, go to your local files, in the Mods folder, delete the modlist.json file

After starting it up, enable the following mods:

MW5 Compatibility Pack
Community Asset Bundle
Mech_Bundle
MercTech Compatibility Pack
MercTechV2
Cockpit Glass

Restart the game and you should have MercTech and Patch Notes on the main screen now. These are the core mods required.