You must have installed Menyoo Mod - https://www.gta5-mods.com/scripts/menyoo-pc-sp ------------ UPDATED
and you must have installed Simple Trainer for GTA V - https://www.gta5-mods.com/scripts/simple-trainer-for-gtav ------------ UPDATED
Go to GTA V root directory - open folder 'menyooStuff' - Go to folder 'Outfit' -
and in Outfit folder drop and paste SDMC folder

IN GAME:

Press F8 two times - go to 'Player Options' - go to Wardrobe -
go to Outfits - go to SDMC.