clean it with a wet and very soft clean cloth and rub gently with ur finger.

The white layer is normal and it's just a layer of breast milk. It need not be cleaned if baby is exclusively breast feeding. It is also not an infection so relax. In fact cleaning the mouth can actually introduce bacteria in an otherwise healthy environment.

You can clean baby's tongue with a soft cotton cloth. Just wet the cloth with water and wrap around the cotton cloth on one of your finger and lightly rub around baby's tongue.

That is common and is called thrush. After a month you can wet a muslin cloth and clean the tongue.