How do I tell my bot when to go to trainer? atm its going there every level (which is not wanted ofc), and also when Im using wlock trainer in stormwind my bot gets stuck on the wall cause its underground and you need to go trough a loop tunnel to enter the room.

Hello, add trainer to your "NPC db" (tab tools) and activate option " train new skills "

But how can I configure WHEN I want my char to go to trainer?

You can't 

Not sure is it working or not, haven't tested it yet.