Body repair/floor pan restoration advice?

i have a 56 buick im in the process of restoring. the floor at the driver side is a little rough, starting from the pedal to under neath the seat. i ripped the carpet out and removed the seats for reupholstrey. i started power blasting the floor andgetting all the surface rust off and gonna put rustoleom primer on it. i also already cut out the rot so now i have space for the sheet metal..alright so now i need advice on patching, im not gonna weld it i want to use fibergl, how wouldi go about doing this? should i bolt the metal on then go over it with gl or what, make frames for the sheetmetal then bolt onto that and body fill everything? im really not sure this is my first car im restoring and i just need some advice, it would be greatly appreciated.