Access to the LANSA system is automatic. Any IBM i user can type in the command LANSA or call program LANSA and the main system menu will be displayed.
However, unless the user has been specifically allowed access to some component(s) within the LANSA system (or is part of a 'group' profile that has) there will be no entries on the main system menu and the user will not be allowed to do anything within LANSA. You set the components to which a user has access using the Review user access to LANSA system on the Housekeeping menu.
You can remove a user's name via the Remove a LANSA User via the Administration menu.