When installed and activated in your MA HUD it enables other people (on other sims) to see that you use Mama Allpa and are interested in an 'encounter'.
After purchasing the finder, installation is easy:
add it - and that is all. it will detect your HUD, install itself, detach.
After installing the finder, you can either call it up via
HUD - Assistant - Add ons - Finder <- this menu holds options for activation and deactivation
or via
HUD - Status - List Finder <- does what it says, gives you a list
lists 3 male and 3 female HUD users - this button is only available if your finder is on - the list considers people who were active within the last 30 minutes.
Allows you to be found
Hides you, you can not be found. List does not work then.