On your driving test you might be asked to perform an Emergency Stop. If it does happen the examiner will ask you to pull up somewhere safe, then they’ll explain to you that they’d like you to do an Emergency Stop sometime after you move off again.
After you’ve driven off the examiner will check all around, and if it’s clear they’ll hold their arm out (hand under the interior mirror) and say STOP at the same time.
Brake hard (but under control) and when the car has stopped, secure the car by putting the parking brake (handbrake) on. The examiner will then ask you to drive on when it’s safe to do so. Definitely make sure you check ALL round the car including blind spots on both sides, because you’ll be in the middle of your lane which means you’re more vulnerable than when you’re parked up at the roadside.
When you know it’s safe, drive on and then that will be your Emergency Stop completed!