The airbus has a variety of modes with which to trap you in the descent. Whilst the 100 miles gives you about 30,000' works the good old Frenchies had to complicate the descent modes!
If you have a way point with a vertical limit on the final approach to your field you can commence descent by 'pushing' the altitude selector and giving the auto pilot a 'managed' descent. This will allow the AP to speed up and slow down within a defined bracket (displayed in magenta on the speed tape) whilst adhering to the altitude limitations as best it can. If they go amber it can't make them and calls for 'MORE DRAG' in the PFD and MCDU. Very ambitious if you are high and heavy! Pulling the altitude selector with the next altitude dialled up gives you 'open descent'. This will descend you, at the best rate, ignoring waypoint altitude constraints, for a given speed. In other words, you dial up 3000' in the height window and pull and it will barrel down as fast as it can whilst holding your selected speed. Want to go down quicker? Use the speed brake. Want to go down really quick? Use the gear! Also you have V/S mode, this will ignore speed to give you the rate of descent, as dialled up in the FCU. That is, if the speed goes below selected then auto thrust will keep it there. However, if you dial in -5000fpm and pull V/S, watch the speed go off the tape! Generally V/S is used for 'finesse' and open descent for 'get me in the ball park'.
The upshot is that if you have a well planned MCDU route with well defined vertical, lateral and speed waypoints then give the 'bus managed nav and descent and it will get you there. If not, there are lots of options to play with.
Enjoy.