How do I select a mesh in edit mode? I want to delete the starting cube. And how do I choose how many divisions a new cylinder mesh has?
You can’t really select a mesh in edit mode (since you’re now modifying the mesh you selected last in object mode).In edit mode you have vertices,edges and faces (selecting a vertex and pressing ctrl+L will select all connected vertices).To delete a mesh,go into object mode and select the mesh via RMB (right mouse button) and press X and then select delete (you should have more options in edit mode for specific things when pressing X)
For the cylinder,in object mode press shift+A > Mesh > Cylinder.Before rotating it or doing anything else you can change the decision count (vertices) in the left lower corner (if you don’t have the menu at the right open then you can Press T to open or close it,the one on the right can be opened and closed with N)