Just to be sure.
1) Download the mod
2) Extract it
3) There should be a file called mods
4) Copy and paste THE FILE with the mods in it, on the DATA folder
5) If there is already a file called mods in the DATA folder, you have to copy and paste THE MODS AND NOT THE FILE from the mods file, to the mods file places in the DATA folder.
Assuming you have done those steps correctly there shouldn't be a problem.
Just to be sure again, these mods will only work on episode 18.1
EDIT:IF that part is correctly done you go to the options menu and from there you can activate the debug menu, the exp share options, the walk through walls etc etc.