We train the bats who are badly injured and have to stay a bit longer in our station, to feed themselves. So you take one bat and a worm and offer the worm to the bat.
When the bat takes the worm, you get the next worm and offer it to the bat. With every worm you get the bat closer to the little bowl where the worms are in. Some bats are very good and start after a few seconds eating from the bowl, others need a couple of days or weeks to learn this.
It's very important to talk to the bats calmly, when they get trained, so they won't get afraid of the bowl and the worms in it. Bats from the same group you can train together so they can see how the clever ones eat from the bowl and they will learn it from their friends. Others of the group need to be trained and trained again. The same with the food goes for the water. You start getting them water with a pipette and then get closer and closer to the waterbowl.