Alot of people are asking about how to have the cosmetics.
The first way is to check the appearances.txt inside the mod root folder which contains detailed instructions on how to use specifics supported cosmetic mods with specific armor sets.
The second way is just to install https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2438621356 and then use any cosmetic mod you want to customize your soldier.

I'll post below a list of mods i use and some of them are also in the appearances.txt already.

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1124164405
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1131360448
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1197817577
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1172570913
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1126848601
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1263866085
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1541284641
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1379500321
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1517244735