Hello, my name is Mark and I will try help you with this.
If you are using the footbrake then you should be using your left foot on the brake and your right foot on the throttle.
When you go to move off you should use your right foot on the throttle a fraction earlier than releasing your left from the brake.
The correct way though is to use the handbrake and not the footbrake.
Do you require any further assistance with this?