Now that you had some time to practice getting used to the water, doing bops, blowing bubbles, putting your face in the water, holding breath and relaxing, it is time we start focusing on floating. However, don't neglect the other drills if you still have some troubles. Be patient and the success will come.
Think of your body as a vessel where your core goes from head to hips. When floating or swimming the head should be in a neutral position. By neutral, I mean ears just below the surface of the water and your eyes are facing the bottom of the pool. The back of your head is dry and your suit is no more than 1.5 inches under the surface. If your head is in negative position, your chin is tucked on your chest and all the water is flowing over your head (NOT GOOD). If in positive position the water is hitting you on your hairline and your legs are sinking(NOT CORRECT EITHER).
You can practice getting into the neutral position by performing so called dead man's float. Now, we need to realize that not everyone will float (for example: women float better than men). So if you are not the lucky floater, you will just have to compensate for your none floating in other way (more later). Let's get to the excercise:
- Take a deep breath, put your head in a negative position (chin on chest), be vertical, let your arms down toward hips - you can imagine they are in the pockets (you will have your feet dangling almost straight to the bottom
- VERY SLOWLY start raising your head into the neutral position, with the back of the head right above the surface, ears under the surface and eyes facing the bottom of the pool. Allow for the hips and legs to ease themselves towards the surface. Do not have any movement in feet or legs (if done correctly, your hips/legs should rise a little)
- Now, slowly ease shoulders, arms, and hands into the streamline position (position where your arms are above your head - like you are trying reach with both hands for an apple on a tree). Make sure you do not raise your arms out of the water, they should rest right at the surface. (if done correctly, your hips/legs should rise even higher to the surface - see the image below)

Some of you will find yourselves laying on the surface of the water. This is brilliant, well done. Some of you will have your feet still dangling down, however, they should be higher than they were originally. Well done as well. It is not a problem that your feet are not all the way at the surface, you will just have to kick more when swimming. Don't worry though, if your feet are not right at the surface, this could be changed by practicing more and more and learning to relax more and more.
You probably ask yourselves. Wow, why is it that my feet are rising. Well, it is simple. Your body acts like a teeter totter with your hips being the axis. Once you get the head in neutral position then stretch the shoulders, arms, and hands in the streamlined position right at the surface, you are adding more weight on one side of the teeter totter, so your legs will automatically rise up. I have included a picture of teeter totter below if you don't remember from your younger days :).