Is it supposed to completly close the server down? if not what am i doing wrong? and is there a way to fix that?

Plugins cannot actually start the server again, you'd have to have an external tool or script start it again.

and how would i do that? just trying to set it up for a guild to play on almost all the time and restarting cuts the lag down a lot

Do u run it locally/dedicated or through a hosting panel?

its a dedicated server i have set up for a couple of friends on my pc. 

would this work for valheim? says its for rust

Archmonger

would this work for valheim? says its for rust

I believe he's just showing an example. The .sh/bat that is created via the uMod install steps would also provide an example of this, which is what I would suggest looking at.

hmm, im new to this kind of stuff so how would i use this?