What is good way of braking?

It is a good practice to use the right brake lever more often than using the rear brake, as the front brake provides more stopping power due to the weight distribution during forward movement. This is true for any vehicle.

Additionally for the Ather 450 (EV), it is a good practice to use regen which acts like engine braking. This increases the range of the vehicle as well as reduces wear of components like brake pads.