Hi everyone!
I’m having trouble kind of “shrink” my score to one page
in Sibelius, it’s two clicks away and Sibelius does all the job
is there any way I can do the same thing in Doirco (automatically and not manually dragging bars or making systems in engrave mode?)
Thank you! 
Video:
Quickest way is probably to insert a frame break at the beginning of the piece, then select the frame break signpost and activate “Wait for next frame break” in the Properties panel at the bottom of the window.
Less quick ways involve tweaking the note spacing and/or vertical spacing settings in the layout so that Dorico pulls it all into one page without being forced.
Thank you Lillie!!
(Note that what “Wait for next frame break” does is tell Dorico to fill all subsequent music in that frame, until the next explicit break. In a project with lots of flows after this one, you might end up with a very full page indeed! So in those situations, looking at the fixed casting off settings, note spacing, and vertical spacing defaults might actually end up neater in the long run.)