We did a little math to figure out how long each beam had to be in order to provide support for the entire structure while providing space for the fascia and a 1/4-in lip on the final Deck surface. We ended up with 123" long beams. So we cut three of those and a shorter one for the back.
The next step was to measure and cut posts for each concrete footing. This was a little time consuming because each post was a different length. We measured and cut one post that allowed the final deck surface to be at the string we measured out then cut another post to allow the beam to sit level. It was nice having Oliver around because he did a lot of the cutting and helping to eyeball all of the measurements while doing the math.