What you feed can depend on your type or breed of goat and your goals. I raise dairy goats so I need to provide lots of calcium and protein that they can turn into milk. If you raise a meat breed you might provide a different mix.
But basically you should feed hay, and depending on what you can get, go from there. Personally I feed my goats a nice quality alfalfa/grass/weed mix hay that I can get locally, then alfalfa pellets, then rolled oats and a little BOSS. (Black oil sunflower seed.) Those are in order of how much, starting with what makes up the most to what makes up the least of the feed.
Are the kids going to be weaned? If they are not, you may need to give them milk for a while. Technically you can wean as soon as they start chewing their cud, but I don't wean mine until they are about 4 months old and some even 6 months. I guess everybody is different, so check if that is a concern.
One mistaken idea that people have is that goats are grazers... in reality they are browsers, like deer, and if they can stand on their hind legs while eating a tree branch that's what they prefer to do. They will walk right past beautiful grass in order to eat roses or trees or bushes. Oh sure - they will eat grass if that's all there is, but goats love to eat a variety. If they can get your roses or trees, they will do that.
