Cannot enter edit mode or change to orthographic view? I'm a beginner to all this video creation thing and started reading the "Introduction" and "Starting" of the Doc. 2.6 Manual. At the end of "Starting" there is "Your First Animation" where I tried "1/2: A static Gingerbread Man". There I had the following problems:


After moving the camera and lamp to the 10th layer the cube was not selected anymore. I selected it by Select -> Select All by Layer. Is this correct?
After using Numpad 1 I hit Numpad 5 but the front view still remained and did not change to the orthogonal view. By the way, why should I use Numpad 1 during this example?
By pressing Tab I could not enter into Edit mode.


Could above problems result from my German keyboard and using Windows 8.1?
No, I don't think so. What matters is that the cube is Active (usually the last selected, with a yellow outline).

In Blender there are three selection states:


Unselected
Selected
Active


There can only be one active object at a time. The active object defines which object will go into edit mode when you press &#8633; Tab, which object's options are shown in the properties panel, etc.

Selecting an object with A, select by layer, etc. will not change the active object.

To make the cube active, click on it with  RMB.
That's odd.. Are you sure the mouse cursor was over the 3D view?
I suspect this is because your active object was either the camera or the lamp, not the cube.

You can tell which layer the active object is on by looking at the layers in 3D view > Header. The orange dot represents the active object: