Hellooo any ideas how to train 8 months old baby sleep on his own please.

I think I sleep train my baby from birth up to present. I know lol. So from birth up to 6 months I turn on a lamp at night and sleep beside him. Then, after 6 months, there are times that I turn off the lamp and he falls asleep easier than having the lamp on. I never needed to rock him cause I never did introduced him that rocking him is for sleeping.