I'm patching the areas where old floor heater vents used to be.

1) Any good tips for getting tongue & groove boards into the gaps between existing boards that I haven't chiselled out?

2) Should I stain the new unfinished boards before or after putting them in the patch?

3) Should I put paper below the new boards (there is old paper in the existing floor between the subfloor and the hardwood floor, I presume as an extra insulator)

4) Do I need a special floor nailgun or will any gun suffice?

5) What type of nail should I use for best results? FYI - My boards are 2 inch by .5 inch t&g white oak.

Thanks for any help

You are going to need to rim off the tongue on the new piece. Trim the piece for the best possible fit. Put some rosen paper down, it stops squeaks, not insulation. Pilot drill holes for 2 1/2 in. finishing nails and drive by hand, don't use a gun for patching. Set the nail heads fill holes and cracks with wood filler. Stain to match once the piece is in place. You might start the staining process by testing various stains and blends on scrape pieces.

Great, answers all my questions. Thanks very much.