more on the left (the master area)
more on the right (the stack area)
Mod1-Shift-, Send focused window to previous screen, if any. Mod1-Shift-. Send focused window to next screen, if any.
How do I get rid of horizontal split in dwm https://unix.stackexchange.com/questions/65889/how-do-i-get-rid-of-horizontal-split-in-dwm
[Solved] dwm - move/toggle current window to second screen/projector https://bbs.archlinux.org/viewtopic.php?id=179227