As I've just mentioned in another thread, your best friend on here will be the 'Search' option.
If anybody is going to provide a link or guide for you, chances are they'll have found it via a quick search on this very forum.
I just searched 'replace boot floor' and it threw up no end of useful replies.
Try it - it's the future.
Boot floor is easy just keep in mind that your best friend will be a spot weld drill and not necessarily a grinder and cold chiesel. Be careful drilling out welds as along the drivers side the tank is very close to the underside of the floor
I agree with Greenhornet, spot weld drill is your best bet (clarke). I only used the grinder to cut up the middle of what was left of the floor to get a loose edge, I then worked around the edge of the floor using the spot weld drill. A small crowbar was also very handy, it helped identify where the spot welds where as I levered up the floor. Some of the welds would have been really difficult to find without it as the floor was sooo rusty