I decided to design my own room in blender, so made a room out of "Plane"-Objects. Now i need some holes in the "walls" as I want to make windows an doors. I have absolut no idea which tool to use to cut something out of a "Plane" a name for a useful function would be enough, anything else should be findable with google.
Btw I'm an absolut beginner so please be precise. Thank You