Help request for screened in patio. I can’t find any advice on building around L shaped beams. I wasn’t sure if I should make the frames the same size as the 6x1 current beams as well. Any opinions, ideas or advice is appreciated.

I want to build a screened in patio. Plan to build wood frames around the current beams and use 2x4’s about a foot up to connect them horizontally, then staple to the beams and cover with wood strips. Confused on how to construct the frames. In the Midwest if it matters. Blueprint and pics via /r/DIY http://bit.ly/2Wzj8qw