when baby doll over on his tummy by his own

A. Hai good evening !! Generally babies roll over by 3-4 months few babies will take time 4-5 months . Once babies starts 3rd month, moving side wards it is better not to leave baby on beds alone . Use pillow or make baby sleep on swing /crib. Do tummy time ,regular massage for muscle realxation,tummy time for abs strength,roll over,neck holding ,crawling..