Hi leney
I started brushing as soon as the first tooth appeared, it’s good to get baby used to having them brushed. Just go with a soft baby tooth brush and I used the aqua fresh kids range which gets stronger as they get older but there’s lots of choice in the supermarkets. You could speak with the health visitor, they usually have tooth brush / dental packs to give away. Don’t forget to get baby registered with a dentist if they’re not already, don’t wait until you have a problem as you might struggle to find an NHS dentist