Bijective numeration is like counting but instead of just going from one number to the next, we give each number a name.
Let's say we start with the number 1. In normal counting, we could just say "one" and move on. But in bijective numeration, we give each number a name that is made up of all the numbers we have seen so far.
So the first number is just "one". But when we get to two, we call it "one, two". When we get to three, we call it "one, two, three".
This might sound like a lot, but it actually makes it easier to keep track of numbers when we are dealing with big numbers. In normal counting, if we get to 100, we just have to remember one hundred. But in bijective numeration, we could say "one, two, three, four,..., ninety-eight, ninety-nine, one hundred."
By using bijective numeration, we can keep track of big numbers without getting confused or forgetting where we are. It's like having a map of all the numbers we've seen before.