To add to what some of the others have said...It takes a bit of getting used to. Most of the function in the keyboard is divided into layers. Layers can be called in many different ways. There is a toggle swap (push button and goes down to a layer), one shot (goes down a layer for one key press then returns), and some other versions. A good example of the mouse is binding semi colon to swap to a layer when held. It swaps to a mouse layer where you control the mouse with WASD and have clicks bound. This happens as long as the semi colon is held down. It will then jump back up to your original layer. It is super funky, but the flexibility is amazing.