To properly answer your question would take way too much space here. However the most important thing you need to learn is the use of the tilt knob. Modern day radar is pretty fool proof and about the only way one can get into trouble is misusing the tilt.
A basic rule of thumb is while at altitude enroute adjust the tilt to show very light ground clutter toward the outer of the screen while in the 80 to 120 mile (depending what range scales your radar has), by doing this it is easier to detect weather and not confuse thunderstorms with ground clutter.
One other thing to remember is that when descending, below the mid-twenties, start tilting the radar up, what could be above you is more important than painting the ground.