Help buffers provide the same commands as View mode. A few special commands are also provided:
help-follow
follow a cross-reference at point
forward-button
move point forward to the next hyperlink
backward-button
move point back to the previous hyperlink
help-follow-symbol
show all documentation about the symbol at point
help-go-forward
go forward to the next help topic
help-go-back
got back to the previous help topic