so everytime i restart my server we go back in and none of our teams are saved how can i fix tht 

There aren't any fixes for this. Although people use https://umod.org/plugins/clan-team so basically whoever is in a clan it will put them to a team automatically. That's what most use in order to fight that team wipe on restarts.

ok where would i put tht plugin to get it working on my server 

You need to have the Clans plugin installed, its a dependecy of the plugin I linked you above.
Install it under oxide/plugins as you would do with any other plugins.