I am trying to play downloaded maps solo and I can't get it to work :(

[massivelegend]

Hello! As the title describes I'm trying my hardest to play a map I've downloaded, and I've gone through multiple steps of editing files so I'm an admin, and going into various menus and I get as far as ''starting map'' with a loading bar but it never loads. Could anyone try to help me please? Or point me in the direction of a thread that explains if what i'm trying to do is possible.

Thanks :)

I apologise if this has no doubt been discussed 100's of times I just can't find any threads that detail what to do, thank you