Our Thetford Bravura model is held to the floor with 2 nuts/bolts, one each side at the base of the toilet. Ours are covered by plastic caps, some models may have a snap on cover to hide them.
Just undo the bolts and lift the toilet and turn sideways to see the valve mechanism at the back of the toilet, the plastic water lines should be flexible enough. Ours was leaking from a split/crack in the water valve (about $50 at our local RV store. Also replace the wax or foam seal ($2-3 part) were the toilet seats to the pipe going to the black tank. Almost all toilets, stick house or RV are held to the floor with the two bolts held to a toilet flange screwed to floor and sealed to plumbing pipe.
Beverley and Ken