Gather a small air pump
Gather airline tubing
Gather an air stone or diffuser
Gather a check valve
Gather suction cups or clips
Cut the tubing to the needed length
Attach one end of the tubing to the air pump
Install the check valve in the tubing with the arrow pointing toward the aquarium
Attach the other end of the tubing to the air stone or diffuser
Place the air stone in the aquarium
Secure the tubing to the tank with suction cups or clips
Plug in the air pump
Adjust the airflow if the pump has a control valve
Check for steady bubbles
Reposition the air stone if needed
Keep the pump above the waterline or use a check valve to prevent backflow