Time for action – pressing A to select all
Press the A key to select all the vertices; this is one of the easiest selections available. It selects all the vertices or deselects them if they are all selected:
Click on the Vertex Select Mode button in the 3D View header button with the LMB so that you can work with vertices.
Press the A key several times.
What just happened?
Pressing the A key either selects or deselects everything. You worked with vertices, but this applies to edges, faces, and objects as well. If you look just above the 3D View window on the right-hand side, Blender shows you how many vertices you have selected as you do it.
Selecting vertices with Border Select
The Border Select mode allows you to select the vertices, edges or faces in a rectangular area. It's a very easy and flexible method.
