You already have one!
Simply put, a budget is how you spend your money. If you receive money (income) and spend money (expenses) you have a budget. What you need to develop is a “Spending Plan.” I prefer this term because budget has such a negative connotation, i.e. “that’s not in the budget”, “I can’t buy this or that”, “I can’t buy fun stuff because fun stuff is not in the budget” et cetera.
So what is your Spending Plan? Would you be able to clearly explain to someone your income and expenses for the month? You should be able to describe your Spending Plan for one month. For example, “This is the amount of money I take home (income) each month and this is how I spend the money (expenses) each month.”
Describe your Spending Plan for one month.