in your case I would do this.
1. feed them at night when they wake up, ONCE a day, about 7 to 9pm at night
2. go to critterlove.com and make up one of their salads (fruits and veggies) freeze it. apples, pears, papaya, peas, green beans, berries, veggie mix, butternut squash (I buy butternut frozen not fresh.) kale.
3. protein - for now you could give them a hard boiled egg or boiled chicken
plain. for the long term you need to either go with OHPW diet or BML is popular.
I think BML you can get stuff at the store. OHPW I order wombaroo and have to
get raw honey and bee pollen. or you can order ohpw from critterlove.
www.sugarglider.info/category/diet/
this website has lots of diet info and instructions and videos.
also go to store and get dried mealworms, petstore or walmart in bird section.
you can get live mealworms at petsmart/petstore. glider love these and will
get some fat and protein from them. I buy the kaytee brand usually.
I have 6 gliders and have bought an extra freezer put in the garage for all
the glider stuff I freeze plus ice cream!