Yes, it is possible (and fun) to create (and publish) your own macros.
The process is mostly click and drag, so you don't really need more than the information provided in the Reference Manual (or by searching online).
Log into MyPresonus and navigate to
https://my.presonus.com/exchange/browse
There you will find a ton of tools, content and yes, macros that others have shared.
Go to the View menu and Choose Additional views, then Macros
It appears in the upper, left-hand corner of your workspace.
Click on the little sprocket and choose Macro Organizer. It will show the list of macros and has a button for creating.
Good luck!