Page 1 to 'First'

Hi. In Engrave mode (in the right panel) I select Page 1. In the ‘master pages panel’ below the Default Page is highlighted. I want that to be the First.
How can I achieve that?

Assuming you have music on the first page, Layout Options > Page Setup > Flows > Use First Master Page > either the second or third option.

If you’ve turned your First Master Page into a title page, with no music, select page 1 in the right panel of Engrave mode, as you’ve already done, then either right-click and select Insert Master Page change from the context menu, or click the LR icon at the bottom the pages section of the rihgt panel (just above "Master Pages). That’ll give you a dialog that’s hopefully self-explanatory.

You just made my day, Leo!