Here's a link to pictures of the erection process at our house. We used a 2 x 4 jig to make sure all the poles were at the correct distance. If your hoops are for example 14' apart when together, you will want your ground poles to be closer than that. You'll want a little bit of tension for structural strength. We also duck taped over the bolts holding the roof ridge to prevent excess wear and tear of the plastic.

Here is a link that might be useful: Greenhouse project