The Designer is the way Bridge Hosts can make their own missions, mod Horizons with their own skins, and integrate DMX lighting as well as many other things. A lot of the specific information will be found in the Modding Section of the Wiki.
List of features, with links to the relevant wiki articles will be added shortly
Bridge Stations : Flight | Tactical | Operations (Comms) | Science | Engineering | Captain
Ancillary Consoles/Displays : Center | Stellar Navigation | Stellar Body | Star System | Alert Status | Shield Status | Cargo Hold | Radar | IRIS
In Progress (Incomplete) Consoles/Displays : Crew Roster | Collision Alarm | Dashboard | Deck Status | Target | Scan | Vessel Status
Admin Consoles : Game Master | Mission Control | Mission Status | Designer