Every model of the Novation Launchpads do the same. They are a 80 keys USB keyboard, automatically recognized by Hauptwerk when plugged in an USB connexion. It does not need an external power supply.
Using a right-clic you can assign the Launchpad a key and a color to every Hauptwerk command (stop, couplers, registration and so on), for any sample-set. Hauptwek will remember your choose and the Launchpad will be configured for that sample-set every time you will use it.
When you press a key of the Launchpad the chosen Hauptwerk command is On (both on the Launchpad an on the Hauptwerk screen). When you press it again, this command is Off. One can not find easier.
The only differences between launchpad models are the price, the size and the number of usable colors. The size of the mini is 18.5 x 18.5 cm (6.1 x 6.1 inches) other models are 32 x 31 cm (12.6 x 12.2 inches). But they are doing the same with Hauptwerk.
I'm using such Launchpad since several years and I'm satisfied: easy, robust and fiable.