With both of my children the transition made little sense to me. They sort of did it on their own. I could tell when the time for change was approaching because, both of them didn't want to take the early morning nap anymore around 9 or 10am. But, they'd fall asleep in the car for any morning outings such as going to the grocery store at 10:30 or 11am. This made things tough sometimes, and I would just turn around and go home or I would try to accomplish a play date or something with one sleeping baby in the stroller. Just being out and about would make my little one wake up after about 45 minutes. She couldn't sleep long around noise and commotion from other kids. So, that would be it for her... a very short nap and then crabby all afternoon sometimes. But, even with one wink of the eye, she still couldn't settle down for an afternoon nap around 3. She had her moment of napping and that was it. I would struggle her through the afternoon naps, because staying awake would usually mean stumbling and getting hurt. It was difficult. But, some transitions are just going to be like that.
We did fall into a schedule most days that we stayed home. Doctor appointment, necessary trips to the grocery store, friends stopping by, caused disruption to the schedule often so that's where things made no sense at all. But, for the most part I could keep her cranky bottom up until around 11:30. Then she's nap from anywhere between an hour or three hours. All of my kids seem to need 6 hours stretches between sleep times. So, whenever she'd wake up, I'd just estimate that 6 hours from that time, she'd be tired again. So, I'd shoot for sleep again at that time.
After this two steps forward/three steps back technique (if you want to call it that), we did progress into a one nap a day routine. Now, she gets tired around noon or 1pm, sleeps till around 2 or 3pm, and then is ready for bed around 7:30 or 8:30pm.
I hope this helps, it's not real specific. But, that is just the reality of how it worked out.
Take care.