You should have posted this inquery in The Competitive Kirby thread, since it's related to that topic. But I'll answer your question here for convenience.
"Position" - refers to what state of posture your character is in. These include: standing, walking, dashing, crouching, jumping, sliding, prone, and ledge.
"Basic Offensive Options" - lists some common attacks you can perform while in a specific Position. For instance, while standing you can: Jab, U-tilt, and Grab
"Additional Options" - expand into some alternate moves. For instance, while Standing, you can: D-Smash, F-Smash, and U-Smash, depending on circumstance and intentions.
"Leads Into..." - refers to which Positions you can move into. Example: while standing you can lead into a Crouch, Walk, Dash, and Jump.
It may take a bit of thinking to see how this all strings together, but it all works. For instance, while Dashing, you can move into a "Jump" Position, which allows you to "Jump-Cancel" your Dash and perform a Jump-Canceled Grab.
Hope this helps. I'll probably include this description into the next update of the guide.