Water supply lines are standardized now and connect to a shutoff or supply with a compression style fitting.
Are the supply lines coming out of the floor a bare copper pipe or PEX? Or is there a shut off valve? If there is a compression ring and nut on the water supply, then that needs to be removed.
If there is no shutoff valve, then you should install one on each supply line (hot and cold). Unfortunately, builders stopped installing these some years ago to save $$ on the unseen costs of a house (which they perceive adds no value to the new home purchaser).
You can get the shutoff valves in straight (when coming out of the floor) or 90 degree - from the wall and for various supply line types (PEX, copper).
If you are not confident in your soldering skills, you can get a SharkBite valve that does not require soldering.
Assuming you have copper supply lines, and are not confident in your soldering skills, this is what you do:
- Turn off the water to the house, and relieve the pressure by opening taps at or below the level of the supply line.
- Have a bucket and some cloths handy.
- Disconnect your current faucet.
- Cut off the top of the water supply pipe with a - to use this kind of cutter, position the cutting wheel where you want the pipe cut and tighten the knob. Rotate the cutter twice, tighten a bit more, repeat until the pipe is cut through.
- Install your new valve - like this
- Make sure the valve is turned off, then turn the water back on in the house and check for any leaks.
- Install your faucet, connect it and check for leaks. Don't forget the teflon tape on the threads before you attach the nut. Wrap the teflon tape around the threads in the same direction as you turn the nut to tighten it.
Use the cloths to mop up any water that comes out of the pipe as you cut it. Put the wet cloths in the bucket to contain the water.