Here are a few things you should consider when training professional swimmer, at infant age
You are going to have to use many tools to be successful. Some athletes are going to learn by doing, and practicing a skill with repetition after repetition. Some are going to have to see a picture or video or what to do. A small portion of the group will be good at hearing instruction and doing what is asked. Stay patient, and remember that you may have to give any one instruction up to three different ways.
Start the practice with the same warm-up every day. Kids are good at routine, and will thrive in an environment where they know exactly what is expected. Give them that routine to kick off each practice. I’ve seen coaches start with 10 minutes of backstroke turns everyday with a lot of success. I’ve heard of starting each practice with a 300 meter exercise: 100 Swim + 100 Kick + 100 Swim. You could do 10×25 Freestyle on 1 minute to start each practice. Whatever it is, keep it simple and consistent through the first few weeks.
Have fun with the kids. If you are not having fun, then they are not having fun…and when they are in a state of enjoyment, they will do well at the beginning stages of their sport. Find a way to make the sport fun for them…and be sure to smile at them every day!