Floor pans. gulp...help...

In the process of doing the body on my 67 fish. Floor pans were rotted out so I ordered both the left and right side front to rear floor pans from amd. I've never welded or cut floor pans out before so I figured id get some advice before I start cutting stuff up. Any advice or a how to in a previous thread would be beyond helpful. Thanks way in advance. Sheet metal isn't cheap and I'm only trying to do this one time. Thanks!