I built a cover for my patio and documented the process. Use this as inspiration and tips for building your own covered patio.
I didn’t record doing the flashing part, but if you made it that far, flashing is a piece of cake. Stick it under the siding and above the shingles with an overlap and nail them in. Seal it up with roof sealant or do what I did and add peel and stick aluminum across the entire length for additional protection.