Mods does not work for me

Hey

I need a little help about mods I tried download several ones but none of them work whenever I try play with them the game is always crush out. Then I watched a video about make mods so I made one basic on that video (on youtube) because I was think that it may should work but samething happened.
I did download the game like 2 weeks ago on steam.

Please someone any idea or suggestion what should I do?