All Themes not working

Hey guys,

I need some help. Im new to this Forum CMS and i can't find anything that works so i ask here.

I've downloaded some Themes from this forum. Also from other Sites but everytime i want to change the Theme, the default theme will still be showed..

Im a noob with this CMS so i don't know what to post or to search for to find the Issue.


Heeeelllpppppppp!!!!

Greetings,