Ditto only connects to receivers that are registered with Ditto. If you are visiting an organization that uses Ditto, simply type the organization's room code into Ditto to connect to its display. If the organization you are visiting does not use Ditto, you will not be able to connect.
In the meantime, check out our AirParrot screen-mirroring software if you're looking to wirelessly connect in places that don't have Ditto. AirParrot allows you to screen mirror to any display with a compatible AirPlay or Google Cast receiver, such as Apple TV, Chromecast or a Reflector-enabled device, at any time.