Need to know what type of floor under the carpet, concrete or wood ? Either way if metal studs are used the track has to be anchored to the floor, same as the wood. its been awhile since ive done residental work. but im sure the carpet cuts back. 2x4 or track anchored to the floor. the studs then sheetrock after the walls/closet if there is base board it needs to be installed to hold the carpet down or new tack strips need to be installed to hold the carpet down,