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?

I clean lo gums with small towel with drink water before teeth erupted. After teeth erupted I still clean the gum with towel plus pigeon toothbrush. step 1 then step 2 then step 3. i dont follow exact months that stated in the pigeon package cause my lo teeths coming fast. i use step 1 when lo 6-8 months step 2 when lo 8-9 months step 3 when lo 9-10 months now my lo 11 months with 8 teeths and i already used small toothbrush bought from daiso.