What do those 4 numbers mean on a disc?
Speed, Glide, Turn, & Fade. Let us explain:
SPEED | 1 to 15
Speed relates arm speed to the manufacturer’s specs of a disc. The higher the speed of a disc, the more snap, spin and rotation required for the disc to perform the way it was designed and as the manufacturer describes it. High speed discs are not recommended for beginners as they require more power to fly properly. Speed 15 Distance Drivers are the fastest, having the PDGA maximum legal wing width. Faster discs cut into the wind with less effort and are best when throwing up wind. Slower discs take more power to throw upwind, but they’re easier to throw more accurately and may actually go farther downwind. Slower discs are perfect for beginners!
GLIDE | 1 to 7
Glide describes the discs ability to maintain loft during flight. We describe this as hover. The higher the glide, the farther down the fairway the disc will carry. Discs with more glide are best for new players, and for producing maximum distance. Discs with less glide are more accurate in high wind situations.
TURN | +1 to -5
  High Speed Turn is the tendency of a disc to turn over or bank to the right for Right Hand Back Hand throws (RHBH) during the initial part of the flight. A disc with a +1 rating is most resistant to turning over, while a -5 rating will turn the most. Discs with more Turn are called Understable and are easier to throw making them a perfect choice for newer players and those without a lot of arm speed. Discs rated -3 to -5 make good roller discs. Discs with less turn are more accurate in the wind.
FADE | 0 to 5
  Low Speed Fade is the discs tendency to hook left (for RHBH throws) at the end of the flight. Fade is rated from 0 to 5. A disc rated 0 will finish straightest, while a disc rated 5 will hook hard at the end of the flight. High fade discs are usually used for Spike and Skip shots.
Disc Golf Terms that may be like a foreign language to new players
Stability: A description of the disc’s flight path.

Understable: This describes a disc that turns right (for a RHBH thrower) during the high speed portion of the flight. Understable discs are easier to throw for less experienced players.

Stable: The tendency of a disc to remain straight through most of the flight.

Overstable: Refers to a flight that turns left (RHBH thrower) at high or low speeds.

Spike/Spike Hyzer: A shot that lands almost vertically and doesn’t skip.

Skip: A shot that is meant to fly after it hits the ground.