On your dock, click the 'Finder' icon(the little half-blue half-white face), and then click 'Applications' on the left. Find the Application you want, and like you said, simply drag it down to the dock, and bam. It will stay there.

Mac Pin

Mar 18, 2020  Pin a note. If you want to keep a note at the top of the list, you can pin it. Right-click and pick Pin Note. Select the note and click File Pin Note from the menu bar. If you want to unpin a note later, follow one of the above methods and pick Unpin Note. If you want to protect a note with a password, you can lock it.

Mac Pin Window

You were talking about trying to do that from the program called 'Launchpad', which is different. As far as rearranging the icons in Launchpad goes, just click and hold your mouse on the App for a few seconds until it jiggles, just like on iOS. Then drag it where you want.