The biggest difficulty when starting a car on a hill lies in the need to coordinate the movement of the feet when using the pedals. There are many techniques in this regard, so let's quickly review all of them.
Are you a beginner?
In that case, the first thing you should do is keep the parking brake on with the lever in the up position. Then depress the clutch pedal and start the engine. Without releasing the clutch pedal, start pressing the accelerator to raise the revs. Only then can you gradually release your foot from the clutch until you feel that the engine is developing enough force to move the vehicle.
The clutch should not be fully released, but only up to the point where friction with the crankshaft begins to occur and the force of the engine is transmitted to the drive wheels. On gently inclining hills, this clutch pedal play may be enough for the engine to develop enough force to move the car, without pressing the accelerator. At that point, lower the parking brake lever and the vehicle will begin to move normally.
This technique is not only useful for novice drivers, but also on hills with a very steep incline.
In case of having some experience, the manoeuvre is carried out in a quite similar way but without the handbrake. Once the engine has started and with the clutch and brake pedals depressed, you must gently release the clutch to the point indicated in the previous section.
This is when the brake pedal can start to release. Often this will be enough for the vehicle to start driving. Otherwise, once the foot is released from the brake, the accelerator must be stepped on gradually.