It’s also helpful when you want to open an app whose name you can’t remember. Not that that has ever happened to me you understand!
To use it just click on the icon in the Dock and Launchpad opens, full screen.
You will probably have more than one page. The dots at the bottom of the screen (red circle) indicates how many pages you have and which one you are on.
The first page will always be the principal Apple apps, but it is easy as pie to move them around. It works like moving apps around on an iPad or phone, but it is easier. Just grab an icon you want to move by clicking on it and holding down the mouse button and then drag it to whichever screen you want it to land on.
As you can see from the image my Dock is really full, but I am slowly identifying those apps I use every single day and those I don’t. The ones I use to open documents are staying. I am in the process of deleting some of the others from the Dock and relying on Launchpad to get to them.
By opening documents I mean that I will drag a Freeway document over the Freeway icon in the Dock to quickly open it.