Get a foot pump with fixed gauge, it will help you in any situation to pump up the wheel to the desired level. Or buy an electric pump that connects to the "cigarette lighter" in the cabin of the car. It should also have included a device which will show the pressure in the wheels.
Remove the cap, it is always located on the valve. In place of the cap, push the hose that leads from the pump or from the compressor. Do not rush immediately to pump, first look at the pressure gauge. If the pressure is below normal, then you need swap space. Norm is the value 2 to 2.2 atmospheres.
Be careful not to exceed, the excess pressure will make the wheel too hard, which reduces the comfort and handling on the road. Sometimes this surplus invalidates the tires – they just burst. When the excess pressure to clear the hose and let the excess air out by pressing on the nipple. At the same time check the pressure in all the other wheels and, if necessary, swap them.
If you have a flat wheel on the road, in the Parking lot or in some other place, then after pumping the wheels check if there is a puncture. To do this, raise the vehicle on a Jack and inspect it, scrolling in all directions. If you see entrenched in the tread patterns nail, screw or any other sharp object, then the repair can not be avoided, and pumping will not help. Well, if you have a spare wheel, then it's simple: Jack the car and replace.
If you don't have a spare, then try to get to the nearest tire store. To do this, inflate the wheel and, without pulling out a foreign object, move at low speed. If it fails to do so, and the spare wheel you have, then you have to carry out repairs on site with the kit for repair of tubeless tyres.