I can tell you without reservation WEAR A SAFETY BELT when installing the roof!!! I did, thinking I wouldn't need it, but twice I hit the deck. Both times without warning. Glad I had the belt around me.
If your roof has any pitch to it, any debris at all like sawdust will cause it to be extremely slick. A trick...go to the store and buy one of the big liter bottles of Coke or Pepsi. Get the high test stuff, not diet. Go up on the roof, shake the bottle violently and loosen the cap and let it spray all over where you are walking. It will really help your feet to stick to the roof. First time it rains, it all washes away.
Good luck. I installed mine (see my profile page) by myself and it all worked out ok. You'll want to get a metal cutting blade for your circular saw and a stick of wax to lube the blade, but the rest of it is quite straightforward.