(C-a <SPC>, C-a n, C-a C-n)
Switch to the next window. This command can be used repeatedly to
cycle through the list of windows. (On some terminals, C-<SPC>
generates a NUL character, so you must release the control key before
pressing space.)
— Command: prev
(C-a p, C-a C-p)
Switch to the previous window (the opposite of C-a n).