Sugar gliders, like other marsupials, have a very short gestation period -- about 16 days. The babies, usually 1 or two, very rarely 3, are born tiny (0.19 grams) and hairless, and have to make their own way into the mother's pouch, where they attach themselves to a nipple. They stay there for about two months.
At around two months they begin to emerge from the pouch a little at a time, taking several days to emerge fully -- the first day you might just see a foot, then a whole whole hind end. It can take a week or so for them to finally let go of the nipple and emerge completely. Be sure not to try to handle them at this time, because they are physically attached to the nipple, and removing them will cause injuries to both mother and baby, and probably kill the baby!
Once they are out of the pouch, the babies may hang under the mother's abdomen as she moves about the cage, or they may stay curled in the nest with the male. Male sugar gliders are very good daddies, and help with the care and feeding of the babies.
If the adults are tame enough not to be upset by it, you can gently remove the babies for a few minutes each day and handle them so they will be accustomed to human touch and smell.
Approximately 10 days after emerging, the babies open their eyes. A month or so after that, they are ready to wean. Some sources say the mother may become hostile toward them at this point, to get them to leave her alone so she can raise her next litter. I have never found this to be the case, but it would be wise to watch for signs of hostility so babies can be removed to safety if needed.
A few random answers to questions I've received on the topic of breeding: