To install simply activate the esp using any mod manager(after placing the esp in the Data folder)
Then when ingame use console:
help "boulder" 4 (Look for the id next to Throwing Boulder) orhelp "hydrant" 4 (Look for the id next to Fire Hydrant Bat)
then
"player.additem id xxx" (id being the one you just found and xxx the amount, which is necessary for the boulder which counts like grenades)