In ~/.config/zellij/config.kdl :

simplified_ui false
theme "pencil-light"
default_layout "compact"
mouse_mode false
pane_frames false
show_startup_tips false

Help command (in a file named zhelp somewhere in the PATH) :

cat<<EOF

Ctrl + <p> PANE
  n    new
  r    new right
  d    new down
  ←↑↓→ change focus
  f    toggle full screen
  e    toggle floating

Ctrl + <n> RESIZE
  +|-  increase/decrease size
  ←↑↓→ increase to

Ctrl + <h> MOVE
  ←↑↓→ switch location

Ctrl + <s> SCROLL
  s   enter search term
  ↑↓  scroll
  PgDn|PgUp scroll page
  e edit scrollback in default editor

Ctrl + <q> QUIT

Alt + <n> NEW PANE

Alt + ←↑↓→ CHANGE FOCUS

EOF