Getting on a Routine

FTM. My son is one month old and I would like to get him on a routine soon. He eats every 3ish hours during the day and can go 4 hours at night. Does anyone have any advice on how to get onto a more firm schedule? As of now I feed him when he is hungry, but to get on a schedule
I imagine I'll need to alter that somehow. 
Any advice about routines is welcome! I have no idea what I'm doing.