Tips/advice on a baby schedule

My lo is 12 weeks old and I'm honestly at my wits end he's growing more and more unsettled as the weeks go on, so far iv just been going with the flow which I realise just isn't working for me. His feeds are completely random (we are now formula feeding) and he fights his sleep all day and barely goes down this obviously means he's overtired and bedtime is a nightmare he will not be put down at night he will only sleep on my chest (I desperately want him in his own crib at the side of my bed)and even then he wakes 5+ times through the night normally having a bottle 3 of those times I need to get him on some kind of schedule to help him settle but I don't really know the best times for him to be sleeping or how long he needs to sleep during the day ect? I'm demand feeding but I don't mind having set feeding times if it will help, someone give me some words of wisdom please!