How far along are you in reading the Bible? reading it is interesting not only to find out what's actually in there, but what actually isn't. I'm probably not qualified to answer since I'm one of the many who did not read the entire thing, but as far as I remember, there's surprisingly very little about the devil in the actual Bible.
In the beginning there's the infamous talking snake of course, but I don't think it's ever identified as the devil. And then "Satan" shows up to tempt Jesus in the desert where "satan" in the context means "adversary", and somehow became a proper name for the devil.
I would not be surprised if what we know, or what we think we know about the fall of Lucifer, comes also from Milton's Paradise Lost, and not the Bible. There are many things about religion that we assume from common knowledge or, dare I say, "pop culture". There's probably way more about Hell in Dante's Divine Comedy than in the actual Bible, where if I remember correctly there's just a mention of the Genna as a place of hellfire and torment and not much more.
Also the appearance of the devil himself - if you picture him with hooves, horns and a pitchfork, that's just because they gave him the trait of old pagan gods that were meant to be eradicated from people's ways and culture once christianity took over. The horns are really the ones of the god Cernunnos, which in turn got them from the deer, one of the most important animals of the forest. The pitchfork is Poseidon's trident, and the hooves are the hooves of Pan. All pagan gods that were associated with the devil to eradicate them, or at the very least, give negative connotations to those symbols.
Again, I'm one of those who never read the Bible front to back so probably I'm missing something, but as far as I remember, what we know about "the devil" comes 20% from the actual religious texts, and 80% from "pop culture" for lack of a better term.