This brings up the base screen. Each base is shown with a view from above, showing where all your rooms are. New rooms cost money to build, take time to build, and money to maintain, so you must plan carefully. For each base you can employ soldiers, scientists and engineers, and their wages form part of the monthly maintenence costs. You can always use engineers to make and sell new tech equipment for a profit, even if you don't want the equipment for yourself.
Research is vital.
OK, you have your bases, employees, and equipment. At the main screen there is a graph button. If you place your radar bases well, you'll soon start getting familiar with the airborne part of the game. As the game progresses you should research better planes and better weapons to help you nail the really big UFOs. Trouble is the advanced fighter planes use up valuable Elerium which you can only get from captured alian ships or bases.