If you wish to Efile you return to HMRC you need to apply to the HMRC for your own User ID and Password. Without your own HMRC User ID and Password you cannot conduct your FPS/EPS efiling or DPS services.
To apply for a HMRC E-Filing User ID and Password click here
Once you get your own HMRC E-Filing User ID and Password you should come back and enter these accordingly in the set up section.