How do you lay out a sheet of vinyl flooring over plywood in a kitchen?

I have an old house and i am remodeling the kitchen. I have old plywood on the floor and I just bought some new plywood and a sheet of vinyl flooring. The guy that is suppose to be putting it in for me may not be able to now and I need it done this weekend as I am suppose to be moving into my house next weekend. Can someone please help me out and tell me how to do it myself?