Engine retarders

I can’t add anything to the post above, however you may find this video helpful. Around 1 minute in, they cover the exhaust brake on a Daf LF - Which I’ve found is one of the most common smaller class 2 vehicles (Up to and including 18T) on the roads
youtube.com/watch?v=iroumPleTNA

You don’t need to know how to use the exhaust brake on test from memory. When you do driving assessments with companies after passing, they will look for you to use the exhaust brake in my albeit experience with driving assessments