• SHIFT z: switch wireframe and object mode
• f: fill faces or edges between edges or vertex
• a: select all
• ALT+a: select nothing
• c: circle select
• b: box select
• SHIFT+b: zoom to box
• SHIFT+s: cursor move or selection move
• w: cycle between selecion modes

• edit → preferences → input → emulate numpa
• enable 1,2,3 switch faces,edges,vertex: edit → preferences → keymap → search mode
  • select mode toggle: ALT+1
  • select mode toggle: ALT+2
  • select mode toggle: ALT+3

Sometimes boolean difference fails. Before try on each object:

• edit mode
• select all vertices A
• vertex (top menu) → Merge Vertices → by distance (this operation remove duplicate vertices)

• select (multiple) object and SHIFT+H to hide others
• recall others with ALT+H

TAB key

• activate Vertex select with 1, Edge select with 2 and Face select with 3

Create new object from selected vertex:

• duplicate with SHIFT+d
• ESC to exit from grab mode
• parent selected with “p”
• exit from edit mode with TAB and you will have two objects