Simple? not to me.... chunky hip bag...help please!

I am new to knitting and just finished the front, back, and strap for the purse. I’m getting frustrated trying to figure out how you attach the strap to the bag even with the instructions that I printed out. I hope someone out there can help me. Thanks…

Is this the pattern?: http://www.theknittinggarden.com/gallery/aug-free-2.htm

If so, the handle is sewn onto the front of the bag, all the way around. Notice the ridge? Then do the same for the back. So the strap makes up the depth of the bag. They don’t tell you to attach one end of the strap to the other, I would align one end with the top edge of the bag, sew the strap and pieces together, then sew the strap end on last.

Good luck!