The Control tab is where you can manually control your printer's movements using the "jog" arrows, or return to the "Home" position for each axis.
The slider bars correspond to override values for Feed and Flow rates— Feed rate is the speed of movement of the printer. The slower it goes, the nicer the print will usually look. Flow rate is the percentage of extruded material that comes out of the nozzle, and should remain at 100% in most cases.
Clicking Motors off will disengage the motors, allowing you to manually move your 3D printer’s extruder assembly and heated bed throughout their ranges of motion — be careful of hot surfaces!