When in copy mode (
<prefix>[), you can move the cursor around like you
would in vim with the directional keys (
hjkl). This works fine until you
want to move up or down through pages and pages of text, such as when
navigating to the top of a long stack trace. One way to get where you need
to be more quickly is by paging up and down.
CTRL-u to page up and
CTRL-d to page down.