Where do i put the file?

[Cudakmik]

i do not know where to put the file, do i put it in custom or like what?

[emilyinure]

you need to download an injector like process hacker, and use it to inject the dll into the game process.

this also doesn't work on the new x64 version on the game. to open the x86 version, you need to go to the game files and open tf2.exe instead of tf2_x64.exe