Hi guys,
a while ago i started to learn blender but had to take a break then (rl issues), now i try my luck again and it seems like i forgot some stuff 
i have this:
but i want to make this like this here, so i can subdivide this part without making it worse:
im totaly lost, sorry for bothering you
I take it you subdivided the sides (left and right) where all the triangles originate seperately. So, in edit mode, you should be able to hit U to undo everything till you get back to before the subdivision. Then select All verts (A) in edit mode and hit W-1 (subdivide).
The triangles are created because Blender only allows polygons with 3 or 4 sides. If you try to make one with 5 or 6 or more it will add an edge to keep the 3 or 4 rule.
%<
yeah you are right. tyvm for the answer