Urine infection very poorly

Been told that a urine infection can make someone very poorly, I didn’t realise, I have never had one in my life.

Can someone advise me the symptoms, what to look for in advance?

NHS on urine infections … full sp :

Urinary tract infections (UTIs) - NHS

I had one that come on in just two hours, when I was at college in Southampton. It was so awfully painful I would have called an ambulance if my husband wasn’t working nearby, so I rang him to take me to A&E!
Symptoms can vary, but in my case it was excrutiatingly painful to wee and I felt terrible. All in 2 hours!

My 95 year-old mum had recurring utis. Elderly people with utis may become confused and suffer delirium.