The kakoune prompt (triggered with :) by default does not support the modal editing keybindings for normal buffers.
It has some annoying properties that it closes the prompt when pressing esc, ctrl-n & ctrl-p are not working.
Some useful things to remember is that you can define your own key maps for prompt mode only:
map -docstring "next" global prompt "<c-n>" "<tab>"
map -docstring "prev" global prompt "<c-p>" "<s-tab>"
map -docstring "select" global prompt "<c-y>" "<ret>"
# prevent closing prompt with backspace
map -docstring "select" global prompt "<backspace>" "hd"
There are also some default key mappings in place for the prompt:
<c-r>.paste the current selection in the prompt<c-r>"paste the current yank register in the prompt