How to take pictures with a DSLR

With all the adjustments that need to manually be made with a DSLR camera how do ever just get to take a shot? I can see getting all the settings right for a still shot but how do manually make changes when your subject, lighting, distance is constantly changing? Such as in sports, do just get a all around setting and just start shooting or are you constantly changing settings? Looks like if you do a lot of good pictures will be lost while the shooter is turning buttons.