Help me understand Assassin's Creed 1!

Hello,

From the beginning of AC1 I have been lost! I don't understand the story, why guards follow me when I run, the GPS is confusing when I am getting closer I got to the next map (after loading) and suddenly im behind from the place I wanted to go, when I try to hide in the from the guards in those yellow grass thingies ( i don't remember the word) I automatically get out so I can't hide!

story is to hard to explain

and also when a game has a tutorial pay attention

u are autimatically jumping out of the haystack because they see where u were u can tell if they see you if the sync bar ( top of the screen to the left of your health bar ) is red and it is yellow when they dont see you that is when you can jump in the haystack. then jump out when it is blue

In my opinion, Assassin's Creed story was very hard for me to understand, but I kind of got it throughout the game. Assassin's Creed 2's story was a lot easier to understand in my opinion.