Gas and Oil Home Heating Furnaces - Adding vents to basement heating ducts

I have two rooms in my soon to be finished basement that aren't heated, and each of the rooms has a heating duct that heats the upstairs running from one end of the room to the other. A heating contractor told me it would just take a couple of vents added to each of the ducts to heat each room. This does not sound like rocket science to me, and it seems like I could easily install the vents myself by cutting through the drywall and the sheet metal. Is there something I'm not thinking of here that makes this harder than it seems?

The part I'm a little at a loss on is the return air ducts. There is a furnace room in the center of the basement (each of the two rooms shares a wall with the furnace room) and I'm wondering if I could just put a vent at floor level on the wall to the furnace room.

Can anyone help me with this? I appreciate it.

thats the way I would do it, sounds good, the return air ducts may or may not have an effect but by just adding a return air vent would help out, and if your furnace is in a room, you can add a return air grill to the bottom part of the return air drop along with the return air grills in the rooms to aid in returning air from the 2 rooms.

My next question will reveal that I am new to this do-it-yourself stuff. I will need to rent or borrow a saw - what type would you recommend for a novice that would limit the chances of cutting my arm off yet still do the job?

Thanks again.

I take it the drywall is already installed?!?!
Well when ever I need to cut a hole in Drywall and be accurate I use one of those small handheld saws (looks like a sawzall blade) and cut out the hole, to make a cut in the sheet metal I use a screwdriver held at an angle, use a hammer to pound the screwdriver into the metal to start a hole to get the sheetmetal snips into, then cut out your holes, you will need a pair of Reds, and greens, (right cut,and left cut) snips, makes it easier.
Good luck