1. you need TheDarthKnight's FREE JL Superman ped: 
https://www.patreon.com/posts/superman-justice-45434536?utm_medium=clipboard_copy&utm_source=copyLink&utm_campaign=postshare_fan

2. You're gonna need to install the ped using Addon-Peds by Meth0d (https://www.gta5-mods.com/scripts/addonpeds-asi-pedselector) 
if you do not know how to install addon-peds follow this video by Games & Graphics (https://youtu.be/8dkj21PoEhU)

3. Replace Superman_JL_Dreadnot.ytd with the one given to you in this folder. 

4. You're all set! Enjoy, and have a nice experience!