Don't even drill a hole in a beautiful new hardwood floor! Install a wall plate with a cable attachment if you're going into an unfinished basement etc.
Locate where you wish to mount it near the TV. First acquire the plate. It can be a stand alone plate if available or get a retrofit box (best option) which has 2 wings that will open and clamp it to the drywall. Not necessary to attach this type of box it to a stud nor is it very possible without removing a big chunk of drywall. Get a drywall hole saw (handheld knife looking saw). Trace the box pattern, punch the saw blade through the drywall and cut out the pattern. You may even wish to save the piece you cut out in case you later decide to reinstall and patch the drywall. Now you're going to need a flexible drill bit intended to drill through the base plate. Got mine at Lowes when I got the plate. It'll cost you maybe $50 total for this project but since you've installed new hardwood $50 ain't #$%*
. You insert the long shaft into the drywall hole and center it on the base plate. It comes with a handle you use to hold it in a vertical position. 2 people are better due to the long shaft. Gotta hold the drill AND the handle. The drill head should have a hole which you can feed a string/wire through to use to attach to the cable to use to fish it out. Drill the hole, feed your cable up/down and through the hole in the box, insert the box into the hole, tighten the 2 screws in the box which will unfold the wings and firmly attache the box, attach the cable to the plate and install that into the box. Viola, nice clean install and no holes in new hardwood. recently did my 7.2 surround and relocated my cable. Good project for a cold #$%*ty weather day.