If they are short haired cats, their eyes will open from day 7, long haired from day 14.
You can start weaning them onto kitten food from 4 weeks, but I waited until TCFKA Diego was getting sick of feeding them. Normally the mother stops feeding them as much when they get teeth in, maybe you can look out for this?
A saucer of food usually works, I started by putting some of the jelly in their mouths and then some small broken up bits of food. They soon got the hang of it.