At what age do you start brushing the teeth of your children? Do we need to clean their gums before they even begin to have teeth?

Hi mummy, I usually take a wet cloth to clean my baby's gums before bath time and also his tongue too as sometimes, they are milk residue on it. When he started having teeth, I would use a small soft brush to brush his teeth once a day. My son is now 1 year old with 7 teeth and I have just started using a 'safe-to-swallow' toothpaste during brushing time.