My aunt had triplets ( 2 boys and a girl) when I was 5, so I remember them potty training - my grandma moved in with them to be the nanny, and she walso watched my brother and I some days in the summers, too. They had three potties lined up in the bathroom, and she would just set a timer, and at first, it was every 1/2 hour, and then later every hour, and extend it as they progress. They all sat on the potty together, and my grandma would keep a water bottle full of cold/room temp water on the side of the sink, after they were all sitting, she would squirt them in the crotch with the cold water, and it would "make them pee" and then they would get praise for going. I don't remember the poop part, they probably just payed attention to when time of day the kids usually pooped in the diapers and had them sit on the potty at that time and read books till it came out.
This was back in the 1980s, so we all wore regular cotton training pants, no pull ups - I just trained my 3 year old about a year ago, and I personally thin pull ups are a deterrent to potty training for most kids, they feel just like a diaper, so they use them like one. We tried them at first, and then just gave up and switched to cotton trainers, happened much faster then.
Good Luck!