Cant get Downloaded Npc's to work.

Hi forum visitors,

I have a small issue. When i download npcs i cant get them to work, not only that but they dont pop up in the npc menu. I do what the downloads say like for example. I downloaded the strider npc. It said extract to addons folder. I did that and it didnt work when it worked for other people. Can someone help me? And please, no trolls or anything…