WireMod doesn't work

Yes, I know that GMod 13 had a lot of code changes, but this isn’t the problem.
I downloaded the fixed version of WireMod, however the add-on didn’t load into the game.
Now I thought: Do this file have to be packed inside a “GMA” file? If yes, how do I do it?

Thanks in advance,
Cajetan.

Wiremod is only officially available from the Wiremod Git repository. Anything else that is available is unsupported. There are very clear instructions available here: http://www.wiremod.com/forum/installation-malfunctions-support/30783-ultimate-guide-downloading-wiremod.html