Imagine a thing that you've always wanted for years. For me it was an xbox. The price of the thing you want is way too high for you too afford, you would have to save up for months or even years just to buy the thing.
Heres where the budget comes in, the budget helps you save money. It basically gives you a limit on how much you can spend every month, so you would save an amount every month and get closer to reaching your goal.
Budgeting can also be seen as a type of self control, it prevents you from over spending every month. It gives you something left in the bank account for emergency use.