One piece Floor pan

[314Chevelle]

I just picked up my floor pan & have all the old rotted floors cut out. Originally I had the 2 half floor section pans but I later decided to go with the one piece because my trans tunnels was rotted & badly cut up from the last owners crappy floor shift hack job.My rockers & floor braces were in good shape so I'll just be replacing the pan. My question is, do I remove the braces & come up from the bottom with the pan & then replace the braces?Do I slide the pans under the rockers & if so how since the pan is so large? My pics show the floors cut out & braces in tact. If any 1 has installed the one piece pan, I'd love some advice because I'd like to start putting them in this weekend. Thanks