First off Congratulations to you. I thought potty training twins was hard, I can't imagine 4. Here is what I did. I tried to potty train them together and it didn't work. So I started with one and let the other one be casual about it. I also turned it into a competition of sorts with my son. My daughter was the one I potty trained first and then my son, and I would tell him to go potty, he wouldn't go so I told my daughter to go potty, once she started into the potty he would get up and run in and go potty before she could get there.
Anyway, I took 1 day and spent the entire time with the potty. Every 15 minutes we would sit on the potty for about 5-15 minutes. Then they would pull their panties up and every 5 minutes I would ask them if they were dry. They had to feel their underwear and tell me if they were dry. Then if they pottied their pants before we went and sat on the potty I would make them take their panties off, then I would stick it in their hands and say "oh gross, this is kaka, we don't kaka our panties" etc. They had to feel it wet and feel gross in their hands. Then they would get another pair of panties and wash their hands.
Once that day was over then I would have them get up in the morning, and sit on the potty. Then they could get their cool panties and start with them. Every hour they would have to go and sit on the potty. Every few minutes I would ask them if they were dry. Then if they pottied their panties they got the gross spiel and had to clean up, but they couldn't wear pretty panties anymore they had to wear plan jane white panties.
Once they started going potty more than wetting I would start by making them go potty first thing in the morning, and then putting on their cool underwear, making sure they knew that they had the cool ones on. Then I would tell them to keep them dry. I would still ask if they were dry, but not as much. Then If they went potty I would wait 2 hours and tell them to go potty, if they didn't go potty then I would wait 1 hour and make them go in and go potty. Pretty soon, in about 2 weeks they both were going potty by themselves without reminders.
I still have them wearing diapers at night, because they are not night potty trained, but they are also just 2. But if they wake up dry it's a big deal we get all excited and tell them what a big girl or big boy they are.
(oh, If they went potty during potty training they got a special treat, for my son it was little ice cream bites, I used dibs.)
Good luck and know that one of these days you'll hear the toilet flush and be surprised that you didn't have to tell you kiddo to go potty.