It's not possible to budget more than your income in YNAB, otherwise you get a bunch of bold red ink yelling at you on the screen! It's important to budget only money you currently have. So for example if you have $1500 in your checking account, $1500 is all you can budget. Until you build up a buffer (spending last months income on this months bills) you are going to budget as you get paid. So if in the next 2 weeks before payday you have to pay for groceries and the mortgage, that's what gets budgeted. When you get paid again, you have more available to budget to cover the rest of the bills that month.
Start out with very simple budget categories. Your pool budget is a perfect example. You don't need a pool budget category. Instead, create a home maintenance/repair category and include all those little misc. expenses in that single budget category. Furnace filters, pool supplies, home repairs, etc. all can go here. I set up my master category as "Housing Expenses" and the categories are mortgage, maintenance/repair, taxes, and insurance. Another master category could be "Monthly Utilities/Services" that will include monthly bills like electric, water, gas, cell phone, netflix, etc. I have a shopping/entertainment master category where restaurant spending, shopping, and entertainment spending goes.
You can estimate monthly budgets for things like pool expenses by looking at bank statements and trying to remember your total annual expenses last year. You can at least get a rough estimate, then just divide that into monthly budgets.