Connects to your Multiboard using these connectors from @DavidD. Shoutout to @MohanDas_1521738 & @GlennBrockett for making my life easier with their models. 

I used thicc infill and Default - Snug supports. 
Challenge Mode: It is nearly impossible to remove the supports without removing the 2 tiny little cones that allow the back to “snap” snug into place. But do your best, I believe in you.
If you fail, just know that everything is gonna be okay, and it's still perfectly useable without the little cones. 
And you're doing great, bud.