I would ignore concepts of race and class when describing Breed/Auspice/Tribe. They're not particularly helpful, the game is classless and saying X is Y class only makes things seem pigeonholed. Because it's really being a werewolf that is both race and class of the wider WoD, individual components of werewolves aren't super analogous to anything but sub-race/class. But I still feel that language is more limiting than helfpful.
For Breed tell them there are three Breeds, one is born in homid, one in crinos, and one in lupus and they stay in those forms and live as those things until their first change. Homids tend to be more in touch with human society, Metis are all deformed and typically discriminated against because of the Litany, and Lupus tend towards the spiritual side of things but living as wolves for their childhood means they can't learn certain skills as easily.
Auspice is a large influencing factor on your societal role, a minor one on your personality, and it dictates some beginning Gifts and their starting Rage. Typically each Auspice has a fairly well defined role in the Tribe, but it's not a set thing. If you're ill-suited to the role your Auspice typically plays then you don't have to play that role. So with that in mind here is what I would say for each. Ragabash woofs tend towards wit, levity, and trickery, but they don't have much of a role and are free to do mostly whatever. Theurges are spiritual leaders and more in touch with the spiritual side of things which tends to make them distant. The Philodox are judges and lawmen, and embody dual aspects of fury and wisdom. Gallibards are the inspiring, joyous and jovial, artists, skalds, and bards and oft leaders in wartime. Ahroun are warriors full of rage and killing instinct, they also lead but with actions over words.
There is too much to say on each Tribe individually but collectively they're a culture. Each just has it's own way of doing things and their own customs and goals.