What
@Fatknee said. You just plug them in. The display's setup interface then includes a settings interface that lets you fiddle with quite a few parameters.
This video from Kyle at Bolton shows how you get to the settings in the LCD3 and the LCD8H - probably the two most popular models. I have both but the vid will make it obvious why I prefer the 8H even though I sort of like the 3's b/w display a little more.
Also, a manual that was written by a native English speaker for the LCD3 is like gold! You'll know why if you see any of the others that appear to be translated from ancient Chinese by a Martian who learned English from a Russian. This manual will also work just fine to explain all the settings for the LCD8H, and probably any of them since I think the settings are more or less common among the controllers. You may need to do some digging to figure out stuff like motor magnet counts and such. Scroll down near the bottom of the page for the one you want.
dillengerelectricbikes.com.au