You actually get to know a few insights from having a business budget, but my recommendation is that your budget is inside your accounting software. Xero makes this quite easy for us to do - It also allows you to know what your sales target needs to be to make sure you pay all your bills, and you earn a profit for your efforts as a business owner.
In terms of what you need to do, it's not something you just set up and let sit in the background. I'd recommend reviewing the actual budget versus actual at least every month, so that you can see what your budgeted expenses were, what did it turn out to be, and if there's any variance that you need to take in mind going forward.
You can also make decisions on whether you need to cut back expenses or increase others - for example you might need to increase more marketing, or sales-related expenses to grow the business.
In terms of monitoring your numbers, having your budget done means you know your sales target. As a sales team, you should review that sales target at least every week (that could be just you if you're your only sales person), but make sure your sales target is front and center at least every week - if not a bit of a daily wrap up, or a daily tally. But it's super important to keep monitoring the sales in your business.