The steps for installing large steel teeth on the Big Mac four-wheel drive are as follows:

1. Prepare tools and materials: large steel teeth, bolts, nuts, wrenches, screwdrivers and other tools.

2. Place the large steel teeth on the front or rear end of the vehicle so that they are aligned with the interface of the vehicle.

3. Use bolts and nuts to secure the large steel teeth to the vehicle, making sure it is firmly fixed to the vehicle.

4. Check whether the large steel teeth are firmly fixed on the vehicle to ensure that they will not loosen or fall off during driving.

5. After completing the installation, conduct a test to ensure that the large steel teeth function normally.