Your second row 64 has 7 modules. But the 64 only has 6 power headers.
You'll need to lose a module or buy a Multi Power Cable accessory.
There's a 16/10pin and a 16pin version:
https://4mscompany.com/modaccessories.php

It looks like you plug the 16pin into a power header and then plug the 10pin (or 16pin) connectors directly to your other modules. That'll make more sense when you have your modules.

Don't forget to upgrade Plaits' firmware so you get the Orange mode!

And post your tunes! : )