It's indeed very cool. Nonetheless, here are some of my explanations on it, and also, one Vex uses which I must say is pretty cool. Despite him being a snake and all.
Fuuinjutsu is indeed complex, and can be used to seal things from people, to chakra, to inanimate objects and even, abstract things like souls z,z It entails the use of seals, that are triggered by a certain stimuli (most commonly, the opponent's chakra), and then activated to perform a certain action, which usually results in said target being sealed into an inanimate object, or chakra leeched from them. Though some other uses are like bring forth, and sealing weapons, to access them easier. We've seen Sasuke bring forth Shuriken and kunai, and even some of that string stuff he uses. Tenten, through the use of scrolls, has seals which bring forth weapons, even a lot of them, meaning the "space" in which things are sealed is large, or rather, undefined. Hand seals or Kanji are used for binding, and chakra, to maintain. Strong enough forces, and certain other "keys" can be used to break, or open seals. We've seen that the Uzumaki are quite epic when it comes to sealing, and were capable of sealing a Tailed Beast inside a baby boy, without hurting him in the slightest. Not only that, but even Kinjutsu, entails Fuuinjutsu (you actually need to have Fuuin before you can get Kin). This is because of Edo Tensei, and some advanced stuff requires knowledge of Sealing. It actually comes fort quite a lot in the manga, from the basic scroll seals, to seals that close the cave where the Akatsuki met, seals that hold Bijuus, Itachi's hax Sasunoo sword that seals people, Shinigami that seals souls, eyes that are sealed to hide something, The sages' weapons thatt are unsealed from a gourd, you get the idea.
Vex's one in the quote. You had Fuuin though? So nothing really new for you. If you understand, we'll move on.