after the end of the trip, you need to completely stop the car;
while holding the car with the brake pedal, tighten the "handbrake";
then you can put the selector in the "P" mode.
Please note that the parking mode has one useful function, which is to mechanically lock the gearbox shaft after the lever is moved to the "park" position. Simply put, the wheels are locked, meaning the car will not be able to roll forward or backward even if the handbrake is not tightened.
If the car is in P, start the engine if necessary, it will be enough to insert the key into the ignition and start the engine. By the way, some automatic transmissions may also require additional braking, otherwise the engine will not start (again, additional protection).
Separately, we note that you can also start in the “N” mode, however, you need to take into account that this mode is a service mode (for towing a car, etc.) and conditionally disconnects the gearbox and engine.

This means that the neutral has no blockages, as in the "parking" mode. In simple words, if you do not press the brake and do not tighten the handbrake, the car can roll over bumps.

It is for this reason that it is better to immediately get used to using only the “P” mode, and not “H” when parking the car. Moreover, the "parking" mode, due to the presence of a shaft lock in the box, allows you to avoid freezing of the brake pads in winter