INSTALLATION:

Open up OpenIV and select edit mode. Locate mods\x64v.rpf\models\cdimages\streamedpeds_mp.rpf\mp_f_freemode_01\accs_001_u and drag the file into the folder and drag your file into the folder.
Do the same for the shirt mods\x64v.rpf\models\cdimages\streamedpeds_mp.rpf\mp_f_freemode_01\jbib_002_u and drag the file into the folder. 

For FIVEM:

Drag and drop the MP files into your clothing folder and ensure it.