The stretch, pad, and skew settings control the overall character shape: stretching (or compressing) it horizontally, padding between characters, and skewing it to create an italic.
The other settings determine how the character is drawn within that space: The shrink and grow settings are applied in succession: you can shrink the segments away from each other, and then grow them outward. The bevel setting controls how many points are used at the corners after growing: "0" or "1" will produce sharp edges, while "3" will be almost indistinguishable from a smooth curve.
To use your font in a desktop application, you can Download font, or to use it in a web page, Copy CSS. You can also bookmark the URL to come back to your work in progress.
You can also control the stencil used to print individual charaters. The same stencil is used for every character in a font: You can drag the circular control points to change the shape of each segment, or you can select a particular character in the menu, and click on segments to turn them on and off just for that one character.