Much like the religion I grew up with - made up of "scripture and tradition." Though much of the tradition may be binding as well. Various notions around the pope are clearly not in the bible. And so on.<quoted text>
Well, here is the rub. Since now that have you grasped the concept, pursuant to our lengthy previous conversations, it is time to move it up a notch.
Minhagim (plural of minhag) are actually part of Halacha (Jewish law - literally translated as "the way") too.
Jewish law consists of both mitzvot (commandments that derive directly from the text (bible)) and minhagim. Mitzvot are universally binding while minhagim are not.
So most pick and choose what to follow.