The darkroom view is where you develop your image.
Darkroom mode is for photographic development of the image that you selected from the lighttable. Numerous tools, named modules, are available for processing that image.
On the left hand side you have navigation, snapshot, history stack, color picker, tagging, image information and mask manager panels, described in Section 3.3, “Darkroom panels”. In the right hand panel you can see the histogram and a list of modules available for working with the image. At the bottom of the right hand panel you can enable/disable the view of individual modules.
You can use middle-click to zoom 1:1. A double middle-click takes you to 2:1. Alternatively you can zoom in and out between 1:1 and fit-to-screen by mouse scrolling. Mouse scrolling while holding the control key pressed gives an extended zoom range between 2:1 and 1:10.
You normally export multiple images from the lighttable view but you can also export the current image directly from the darkroom by using the shortcut ctrl-e. Export parameters are then those currently selected in the lighttable.