Refer to the help topic Civil Tools -> Civil Accudraw -> Accudraw Tool Access -> Shortcuts
Some other tools will have options to use the "ALT" key to lock the start/end stations... for example when creating a partial offset or a new corridor. In those cases the ALT option is shown in the heads up display. Some of the accudraw shortcuts generally apply to heads up display such as END, left/right arrow, TAB & ENTER.
Regards
Paul