By default, clefs are shown at the start of all systems. You can hide/show clefs at the start of single-staff systems from the second system onwards in each flow independently.
Hiding clefs on single-staff systems after the first system is a convention used in hand-copied lead sheets, usually in combination with hiding key signatures and showing systemic barlines.
Procedure
Result
Clefs are hidden or shown at the start of single-staff systems from the second system onwards in the selected flows.
Note
Clefs are always shown at the start of systems that contain more than one staff.