How could I use it without posframe?

[yhslai]

I added the suggested config to my init.el:

(use-package evil-owl
  :config
  (setq evil-owl-max-string-length 500)
  (add-to-list 'display-buffer-alist
               '("*evil-owl*"
                 (display-buffer-in-side-window)
                 (side . bottom)
                 (window-height . 0.3)))
  (evil-owl-mode))

evil-owl-mode is activated as expected, but I still don't know how to see what's inside registers. The README says:

Press q, @, ​"​, C-r, m, ​'​, or ` to view the popup, press C-f or C-b to scroll it, and input a register or mark to make the popup disappear.

But none of these works for me. I suppose these keybindings only work with posframe on?