Когда нажимать клавиши по очереди, а когда одновременно, чтобы вызвать сочетание клавиш?

[pfaffman (Jay Pfaffman)]

Control, alt, and shift are modifiers. If you press and release them, in, say, your word processor, nothing happens.

If the key does something by itself, then you press and release it.

Edit: oh, but I get that the documentation should be clearer.