Ground plane tutorial

He guys,

making my first PCB with Fritzing right now and i find it pretty easy to learn in general. However i am struggling to create a proper ground plane, which is quite important to me as i am creating a relatively dense dual layer SMD board. I can find a lot of specific questions in the forums about ground planes, but i somehow missed a place which would explain in detail how to create one, like a tutorial or simple reference manual. I would be happy about any help or link to a tutorial or similar, as i am quite stuck here.