Help me get my 4 month old to sleep in her crib for naps and bedtime!!

What's your 4 month olds schedule?? Bedtime routine? I'm currently trying to sleep train my LO.. she's been sleeping with me for about a month for both naps(in carrier) and at bedtime(bedsharing) I'm afraid of sids and also don't wanna create bad habits that last forever.. I figured better now than later right.. well we are both having a hard time with this. I can't stand to hear her cry.. I let her cry for 5 min after putting her in her crib awake but sleepy.. then I go in and rub her tummy and reassure her then leave again and repeat until she's sleeping but then she only sleeps her a bit and wakes up again then I start all over.. how do I know she is waking cause she's hungry..? Doc said she can go 5-6 hours with eating but man she's still eating 3 hours during the day.. it would make sense that she's hungry in 3 hours not 6 hours.. she's doesn't have hunger cues she goes from being okay to starving btw.. routine is bath bottle play a bit like talk to nothing crazy cause I don't want to stimulate her before bed(so she's up for a bit after eating) hugs prayers then I lay her down.. this is all around 6-7 that I start this routine.. and for naps.. she only sleeps by her self for 15-20 min!!! Please help me I'm getting stressed! I breast feed her btw