Weaning is a difficult time for a kitten. He has become used to nursing on his bottle and may be a little reluctant to give it up at first.
The first step is to place a little warmed formula into a small bowl or a saucer, or better yet, a jar lid. For some reason kittens do really well with the jar lid, perhaps it is just easier to manage. Wash the jar lid in hot, soapy water and rinse thoroughly. Dip your finger into the formula and get the kitten to lick it off your finger. Do this a few times, each time lowering your finger until it's at the level of the formula. The idea is to teach him to lap the formula from the bowl. Don't be discouraged if he doesn't catch on the first time. It often takes a few times for the kitten to learn to eat from a bowl.
Once he is lapping formula from the bowl, you can gradually mix in a little wet kitten food. Do this by mashing a little canned food, add formula and mix thoroughly until you have a milkshake-like consistency. Gradually decrease the amount of formula and increase the amount of kitten food over a few days until he is eating just kitten food. You can also continue to give kitten glop in solid form, instead of liquid. Feed him small amounts about 5 times a day.
Continue offering formula in a bottle after he has first learned to lap from the bowl. Once you are confident that he is getting enough food by himself, withdraw the bottle feedings. During the weaning process, he may dip his paws or walk in his food. Although messy, this is a natural part of weaning and his way of exploring this new food. You can lay newspaper under and around his bowl to make cleaning up easier. This is another reason a jar lid comes in handy. He can't really walk in to the whole thing and rarely do the lids tip over.
Don't forget to have fresh water in a bowl alongside the food for him to drink. If he is eating but not drinking water, you can gently give him 5cc of water with a feeding syringe, a few times a day until he begins drinking by himself. Give this water slowly. Do not force it down his throat quickly.