Replacing or repairing a toilet requires a good deal more patience and tolerance for dirty jobs than is involved with most household repairs. One of the most laborious repairs is replacing the wax bowl ring that guides water from the toilet down into the toilet pipe. When this ring leaks, it can be a messy bathroom disaster, and replacing it is no picnic. A ring is made of an extremely sticky wax which must be scraped off before it can be replaced, and it is often rather dirty after years of use. Wax rings do work well for many years, but there is a type of toilet bowl seal made from rubber which can be easier to install and more flexible in certain situations.
Shut off the water valve to the toilet.
Flush the toilet, draining all of the water from the tank, and plunge down any remaining water in the bowl.
Use a crescent wrench to remove the nut that connects the toilet's water supply line to the valve you just shut off.
Remove the hold-down nuts (or "Johnny nuts") on the base of the toilet.
Remove the lid from the tank.
Grab the bowl right behind the seat, and lift the whole toilet off of the bolts (you might need help for this step, as toilets are heavy).
Place the toilet on the ground so that the seat is facing down, and you can see the inlet where the old wax ring is.
Scrape the remnants of the old wax ring off of the flange (the place where the toilet rested around the drain in the floor) and from the base of the toilet using a putty knife.
Use a spray lubricant to remove the remnants of wax from the base of the toilet that you couldn't clean off with the putty knife. The spray lubricant will soften and loosen the hardest bits of wax.
Apply the adhesive from the rubber seal kit to the seal according to the manufacturer's instructions, and place it into the toilet's discharge outlet. Allow it to dry, also according to manufacturer's instructions.
Place the toilet back on the drain, making sure to align the seal with the drain properly. Again, getting some lifting help will allow you to do this more accurately.
Screw the hold-down nuts back onto the bolts, reconnect the water and turn the valve back on.