Keep in mind that each stick needs to bounce off the drum twice in a double stroke roll. Therefore, before you try the roll, you must practice to bounce the sticks twice with each hand.
In order to be efficiently able to control the bounce, you should push down with your hand after the first bounce, and then after the second one, you should release the pressure.
To see what produces the best sound and effect, you can experiment with various methods of applying pressure. Keep in mind that speed is of extreme importance in snare drum roll and experimentation will allow you to understand which technique suits you the most. It must be remembered that bounce will be faster if you press the stick down harder.
Practice bouncing sticks in succession
Having developed harmony between both your hands while bouncing the sticks, the next step for you is to practice bouncing sticks in succession which would create the roll.