This is very small manual with most common shortcuts.

SHIFT + F2 -> open new window
SHIFT + F7 -> Not sure, but sometimes without it don.t activating all commands.
SHIFT + F8 -> tile windows vericaly, i more than 2, then differnet variations.
SHIFT + F5 -> refresh all windows
SHIFT + F6 -> close byobu
SHIFT + Arrow (depends from window location) -> Move between windows
SHIFT + LeftAlt + Arrow (depends from window location) -> resize window

byobu new -s my-other-session -> start another session

type “Exit” to close unwanted window

byobu-enable -> enable byobu to start automatically with system
byobu-disable -> disable byobu to start automatically with system

If multiple sessions started, should ask which session to use.
If want to use multiple, recommend to name it nice, as its can not offer session choice.
For example, byobu new -s session1 , byobu new -s session2 …

May be different on different byobu versions.

Full list of commands can find in https://www.byobu.org/