Go to the supply house first to buy a new wax gasket. Close off the water to the tank; there is a hand valve behind the tank. Flush the tiolet to remove the water making the tank lighter. Unscrew the nut that fastens the feed pipe, usually 3/8-inch tubing to to tank. Loosen and remove the nuts that are under the cups at either side of the bottom of the bowl. Gently rock the bowl, making sure there are no other bolts or lines holding it down (there usually aren’t.) The bowl can be removed.
I would really prefer a solid concrete base below the bowl, so that there was no linoleum or air spaces beneath the bowl to accept liquids or permit movement of the bowl. I would rather leave the bowl alone and set the linoleum around the base. If these faults are already there, this is an opportunity to correct that.