A budget is not a punishment. It is a plan you make on purpose, so that the month does not make it for you. You can build a workable first version in a single evening, and improve it later.
Start with what actually lands in your account
Use your net income, not your salary. Net income is what remains after tax and deductions, and it is the only number your bills can be paid from. If your income varies, use the lowest month from the past six as your planning figure.
Separate fixed costs from variable ones
Fixed costs are the same every month: rent or mortgage, insurance, phone, subscriptions, minimum debt payments. List them first, because they are predictable and they set the floor of your spending. Variable costs come next: groceries, fuel, eating out, household items. Look at the last two months of statements rather than guessing, because guessing is almost always optimistic.
Give every remaining dollar a job
Subtract fixed and variable costs from your net income. Whatever is left is not spare, it is unassigned. Assign it deliberately, in this order for most people starting out: a small starter emergency fund, then any high-interest debt, then longer-term saving and investing. When income minus every planned expense and saving equals exactly zero, you are running a zero-based budget.
Make the plan survive contact with real life
Two habits do most of the work. First, automate the transfers you decided on, so saving happens on payday rather than whatever is left at month end. Second, book fifteen minutes a week to check the plan against reality and adjust. A budget you revise is working. A budget you abandon in week three was too strict.
What to do next
Write this month down before it starts. If a term here is unfamiliar, look it up in the A-Z knowledge base, where every entry has a plain definition and a practical example.