Kerbal Space Program (KSP) : How to transfer fuel after docking

So I ve been looking for an answer to this for a while now, I was docked and didnt know what to do after.

Tried right-clicking different fuel tanks, no dice. Finally found the answer somewhere.

 

alt + right click on the tanks you want to see the transfer happen between. This will give you the “in” and “out” buttons.