What is the easist way for changing an A4 portrait score to A4 landscape

Dorico 3.5 Windows.

Hello.

I have a lot of music for guitar as well as for piano that I will need to change from A4 portrait to A4 landscape (to display on youtube).

I have been following the videos, and there was something about locking the positions of the systems, but I can’t remember which video that was!

Could some kind soul help me out here.

Thank you.

Paul.

Layout Options > Page Setup > Page Size > Orientation - set to Landscape.

I’m not sure that locking systems (or their positions) is helpful, here, as you’ll presumably want Dorico to shuffle bars around in order to fill out systems that will be wider in landscape than in their current (portrait) form.

I generally just add an entirely separate landscape layout for this purpose so it doesn’t disturb any other layouts already present. That way systems will flow naturally according to Dorico’s routines according to the layout parameters you have set, and setting system breaks need only be set where you wish to override the existing casting off.

I also copy down the settings I use for the landscape format so I can use it agai in subsequent files as needed.

Thank you Leo and Derreck for your suggestions.

Best wishes and seeya.