Please enlighten me on how people and countries differ in the basic concepts of having income, outgoings, and debts

For example, people don't tend to own their own currency. I'm sure you can think of other differences.

Does that mean the UK doesn’t have income, outgoings and debts?

It's much too reductive a framing, IMO. Public sector spending is not, majorly, an "outgoing" of "the UK" in any reasonably comparable way to an individual's spend - rather, public sector money generally funds services within the UK which employ individuals who a) pay income taxes directly b) spend their income in other parts of the economy, where VAT/corporation tax/etc feed back to HMRC, and companies profit and grow.

It's really nothing like an "I've spent £5 on a beer and now that fiver is gone forever" outgoing, in scale or effect.