How do I set up a budget?

There are numerous templates available online to choose from. If you already have our book, there is a simple budget example there that you can use and customise as you need

Do I need specific software to set up a budget?

No you do not. You can use anything. Even writing it down and using a calculator is fine. Excel just makes it easier and sometimes quicker.

Why can’t I budget to spend more money than I currently have? I’m getting that money in a few weeks anyway

You can only spend what you have. If you are definitely receiving money in the future you can plan how you want to spend it once you get it, but you cannot spend it until you have it.

How do I budget if I have variable income or a nontraditional pay cycle?

I would recommend that you then work out what your average monthly income is so that you can plan for the minimum that you will have. If you get extra money in a month, you can plan how to save it for the months when income is less.