first you need to go to this link
https://forums.terraria.org/index.php?threads/1-3-tmodloader-a-modding-api.23726/

and then scroll all the way until you see this

and then you click on the button for your oporatng systim, and it giveth youes the files.

Nw th nxte stpe, moree likeljyrh the hardestrs, is htgteting the fl,iles in.

1nce u open the filess, you should seethis

thiss isnot a requiroesd step, but go in2 the fielsl, and rename the terrararia.exe isidne the zip to zomething else so u dontned to reinstall the gaem

thengo2 this place

and drag the fles theree