Step 3 · Remove Tank Bolts
Look underneath the rim of the toilet bowl where the tank sits. You will see the ends of two (or sometimes three) bolts with nuts on them. To remove these, you need to prevent the bolt from spinning inside the tank while you turn the nut below. Use a screwdriver (usually a flat-head) to hold the bolt head stationary inside the tank. With your other hand, use a deep socket wrench or an adjustable wrench to turn the nut counter-clockwise. If the bolts are severely rusted and won't budge, your best option is to use a mini-hacksaw to carefully cut through each bolt in the space between the tank and the bowl.