Flat

You can throw it flat which will cause the disc to fly its intended path and should be what you practice first before moving onto the other two ways. Here is an example of what your disc should look like when you release it.

Hyzer

As you can see in the throw the disc's left side is dipping lower than the right. This will cause the disc to curve left as it is flying. And depending on how it was used it can either enhance the natural curve of the disc in the beginning of its flight or negate it so the disc can do what it's supposed to at the end of its flight while flying straighter.

Anhyzer

This type of throw is like the one prior as the right side of the disc is tilted down causing it to fly to the right in the case. This has similar properties and uses as the previous throw and knowing which to use in any given situation will see you getting further and closer on target to where you want to be.