Seed is a game for telling stories about adventures - and there's a lot that can happen on adventures. Plots can be hatched to kidnap someone while the queen is busy watching a stage show, ancient mechanisms can bring forth a ruin that has not seen light for a thousand years, and two brothers can find themselves on opposite sides of a vicious war.
Most of these things can be played through based simply on the desires of the group and the natural flow of the game, with Seed content to remain meek, merely piping up, from time to time, with "hey! I have a fun combat game for you to play!" Occasionally, however, you might like a system to intercede, or the course of adventure might in some way affect the course of characters statistically.
For this, Seed provides a bit of structure, some skill checks (if you like them) and a few recommendations.
The rules for Skills create the framework for using result checks to model actions outside of battle, and for modifying those result checks using character traits.
The Talent System is the Seed system for skills that focuses on individual characters and checks are rolled as they come up.
The Fortune System is closely related to the Talent system, however players roll skill check dice in advance and apply the results however they feel.
The Reel System functions much differently from the other two, and puts a heavy focus on party cooperation to pass skill checks. Skill checks are also a bit more involved than a single roll.
The article on Adventure Mechanics contains information on how things within the world of play might affect the characters mechanically - the rules for recovery through rest, sanctuaries, encountering monsters, and so on.