Help with Assassin's Creed

My question is:

A)How do I save game, before turning system off. I've gone to options but I don't see anything like save/extit, etc.....
It seems I have to finish entire/full block for system to auto-save otherwise it won't save if I turn-off without finishing entire block. Is this possible?
I know it automatically saves each time a flag is found and/or some task is completed but if I turn-off consol, all will be lost, unless I finish a block.

B) How do I go from one block to another?

Thank you,