You shouldn’t need to use your left foot at all. Right foot off the accelerator on to the brake, it’s the same principle in a manual car. One of the first things to master is the thought that you may stall the engine when braking. Once you realise you can’t it becomes simple.
One thing no one has mentioned is using the kick down when overtaking.
it’s easy to demonstrate but not so to explain. Basically when you want to overtake instead of changing down gear for acceleration you press the accelerator straight to the floor and the gearbox changes down itself to give you the acceleration needed to overtake. Hope that makes sense.