Construction worker

I need some help in building a garage. I dug out a new footing which is 25 feet long and 4 feet deep. I'm having a new footing poured in a week. After the footing is done, he wants me to start my wall on the new footing which is going to extend the wall out by a foot. Some framework will have to come down because my framing is not completely straight or level. He recommended while waiting for concrete to get poured I could build my wall on ground and then lift it up on the new footing. Let the roof tresses dangle and lift it up to new wall filling in the gaps. This is very difficult to explain so a lot of this will have to be seen in person and explained. New ideas are welcomed also. Hope some one who has time can help.