First of all, check the pressures of each tyre with a pressure gauge as you may have a slow puncture which will just be hidden if blindly inflate it.
Buy yourself a tyre compressor which comes with a pressure gauge as you won't always be near a petrol station.
Tyre pressures are given in two unit types, bar (2.4) or psi (35). Use the number which your compressor pressure gauge measures in. Many read in psi these days.
Pressures are sometimes different between the front wheel and the rear wheel, hence the two columns splitting the diagram of the car between front and back.
You will have different lines with different pressures depending on whether you expect your car to be fully loaded with people and luggage.
There will be different lines for different tyre sizes too, so use the appropriate line for you.