So do you just thrown and anchor out the back cab when you want to stop or do you just have to time when to take the power off and then coast into stations
No, don't be ridiculous. We use a parachute.
Seriously though - 373 doesn't use a 3-step braking system - there are no discrete "steps" in it's UIC EP system or the rheostatic brake. It's a TGV braking system through and through.
In general, high speed trimming is done by rheo only, bringing the train to a station is done using both until about 40km/h when it's discs n' treads only.