EditMode

When working in 3D space, you can basically perform two types of operations: operations that affects the whole object and operations that affect only the geometry of the object itself but not its global properties such as the location or rotation.

In Blender you switch between these two modes with the TAB-key. A selected object outside EditMode is drawn in purple in the 3DWindows (in wireframe mode). To indicate the EditMode the Objects vertices are drawn. Selected vertices are yellow, non selected are purple.

Vertices can be selected like objects with the RMB, holding SHIFT allows you to select more than one vertex. With some vertices selected you can use GKEY, RKEY or SKEY for manipulating the vertices like you would do for whole objects.

Add a Cube to the default scene. Use the 3D-cursor to place it away from the default plane or use GKEY to move it after leaving EditMode.

Switch the 3DWindow to a side view (PAD3), select the cube if it is deselected and press TAB to enter the EditMode again. Now press BKEY for the BorderSelect and daw a rectangle with the LMB around the top four vertices of the cube (you can only see two vertices, because the other two are hiden behind the first two!).

The top vertices change to yellow to indicate that they are selected. You can rotate the view to make shure you really have selected four vertices.

Now press SKEY and move the mouse up and down. You see how the four vertices are scaled. Depending on your movement you can make a pyramid or a chopped of pyramid. You can now also try to grab and rotate some vertices of other objects to get a feeling for the EditMode. With WKEY you call the "Specials"-menu in EditMode. With that menu you can quick access functions needed often for polygon-modelling. You can find the same functionality in the EditButtons F9.