Producing every string of a given length using some range of characters
There is not much to understand about "brute forcing" something. "Brute force" does not mean a particular algorithm.

"Brute force" simply means that instead of using a clever algorithm to simplify a problem (simplify here means reducing the running time) you just test every single possible input to see which one produces the right result.

For example in password cracking, "brute force" means calculating every single possible password and testing them one by one. A smart algorithm would try passwords that are based on names and such first, because we know those are used way too often.

So, first of all, you need to clarify the problem that you are trying to solve through brute force.