selectp -t 1 # select the first (1) pane
splitw -v -p 20 sudo journalctl -f # split it into two halves

selectp -t 1 # select the first (1) pane
splitw -h -p 40 sudo -i # split it into two halves
splitw -v -p 80

selectp -t 1 # go back to the first pane