There is tire pressure in the general instructions. If there is a barometer, it can be inflated according to the above requirements. The simple method is to squeeze the tire hard by hand after deflation, as long as it is not obviously sunken, or you can try it by two people, as long as it is not obviously flat.

Fill the air every other week, and there should be a slow exhaust at this time. Check whether there is any foreign body stuck in it. Pedals are mostly vacuum tires, and things are stuck slowly. Also check whether the air nozzle leaks, whether the tire is aging and cracked, and whether the joint between the rim and the tire leaks.