I have a lot of experience in the art and practice of brewing beer. I've competed in club level contests and done well. I've brewed a great many 5 gallon batches since the mid-90's. This is a really complex and nuanced subject and lots of work but enjoyable too.
First thing. Don't buy any equipment...yet. Especially a "Mr. Beer" kit.
Second thing. If you really want to understand the process start by reading Papazian
. This book will help you fully understand the subject while having fun with it.
Here is the best bit of advice I ever got on the subject:
Everything...EVERYTHING that touches the wort must be cleaned and sanitized.
Let me know if you want to give this a try and what your budget is.