Check the tire pressure on the sidewall (recommended PSI).
Remove the valve cap from the tire valve.
Press a tire gauge onto the valve stem to read current pressure.
If the pressure is low, attach an air hose to the valve (or use a portable inflator).
Inflate in short bursts, rechecking the gauge frequently.
Stop when the tire reaches the recommended PSI.
Remove the hose carefully to avoid losing air.
Recheck the pressure with the gauge.
Replace the valve cap tightly.
Repeat for each tire, including the spare if applicable.