You have the Harris #5 adapter kit? That's what you need.
If you have standard handguards, remove the handguards. Remove the heatshield from 1 of them. Insert the studplate into the #3 hole from the front. Reinstall heat shield, reinstall the handguards. Install the bipod.
If you have a Vmatch, you will need to drill a hole in the tube. You don't have to remove the tube, just slip a piece of metal between the tube and the barrel to keep the drill from nicking the barrel when you drill through. Take some needlenose pliers and insert the studplate. Place washer and stud into it from the outside and tighten. I ended up trimming 1 end of the studplate, and had to countersink the washer a little so the stud wouldn't bottom out.