Technically its Plug and Play, but for best results depending on where you live and the EE Coverage you get, its best you spend some time to position the Router (out of the Box) in various positions around the House ie, Upstairs / Downstairs, Window Sills, North / East / South / West of the Property etc, in order to get the best Signal Reception from EE and the best WiFi Reception for your Devices etc.
The above is something you can do yourself, should be a one time set up and certainly doesn't require any Engineers to visit you.
