Gannet Fan, your height shouldn't stop you from adopting the brace position. It's not that hard to rest your head on the seat in front, unless you're super fat, in which case you just lean as far forward as you can.
Frnikolai, in a forward facing seat, you tuck your lower legs under, usually by pressing the backs of your ankles against the luggage bar of the seat behind you. This helps to stop your lower legs flailing about if forward motion stops suddenly. If you seatbelt is tight, your knees/upper legs shouldn't move too far forward.
If you seriously can't understand the safety card, you can ask for clarification (you'd be surprised how many people can't work their seat belt), and we'd be happy to help. But please don't argue with the flight attendant about its merits, we've got more important things to do.