What is the purpose of Layouts that are on the right side of the Setup mode?
They are the things you end up printing. They contain combinations of Flows and Players that are or aren’t playing in Flows.
e.g. a Full Score layout, a Piano part layout… etc
If you’re writing solo piano music, there is no need for a Piano part layout in addition to the Full Score layout. That’s just how Dorico handles all projects. You can safely delete one, or keep both.
In projects with two or more players, the Layouts Panel has a “killer-app”-level feature that allows the user to copy (propagte) a layout’s properties to others. This can be a real time-saver!
I’d recommend spending a few minutes reading this page in the Operation Manual. It introduces the key terminology you need to understand Setup mode, and explains their purpose and benefits:
Will do thanks.