Before starting to own your first drone its good to know at least the basic of how such an aircraft works and dynamics of flight. In general manned or remote controlled aircraft have the same mechanism. So we will talk about how a typical plane works and how it's related to a quadcopter drone.
Surrounding air is the main factor for a good flight and that's what makes the aircraft to lift. An winged aircraft (eg: commercial jet liners) wings are shaped to make air move faster over the top of the wing. When air moves faster, the pressure of the air decreases. So the pressure on the top of the wing is less than the pressure on the bottom of the wing. The difference in pressure creates a force on the wing that lifts the wing up into the air.
Now quadcopters also have the same principle. they need air but since they are VTOLs (Vertical takeoff land) how it manages air to propel the aircraft is different. With it's four down facing propellers spinning at high speed, make force against the surrounding air. As a result of that the air gives a force against the drone which makes it fly. This is simply according to Newton's 3rd law.
With the above descpription we know how an airplane or a quadcopter fly. but now the question is how does it control it's directions. in a normal airplane there are main components named as Ailerons, Rudder and Elevators.
Ailerons control the Roll of the plane (Roll: banking the plane to left or right)
Elevators control the climb of the airplane (Pitch)
Rudder turns the plane to left or right (Yaw).
In a quadcopter it doesn't have ailerons, elevators or a rudder to do the maneuvers. All the controls are done by motors and its corresponding propellers. changing the speed of the motors can direct the drone in the desired path.
Also note that motors are not rotating at the same direction. in a quadcopter two motors are rotating clock-wise (CW) and other two are rotating counter clock-wise (CCW) hens it will cut excess force generated by the motors and balance the unit properly.
Most of drone users mistakenly think propellers are also the same but they are shaped only to work with its corresponding motor. always look for the manufacture's manual before fixing the propellers on to motors.
*most common drone designs have the same flying principals.