floor pans

Okay, weather is good for tomorrow. Question, if part of the floor pan is lapped in do I weld from the top and bottom or just the top
watching u tube videos seem to show both ways. Never have done this before and really want to do it correctly.
Thanks
in a perfect world that would be the way to go, but... no. that's where I used the neoprene roof caulk. if you really want to do it 'right' you probably either need to do the entire pan as the factory did or butt weld pieces in, so nothing overlaps.