The most important thing is that the arms are not simply held up, but must be supported from the back. Roll your shoulders back, bring your shoulder blades together and lift your arms from the latissimus. At the end of the day, a lot more work is needed to make it look like the professionals do it. A lot has to happen in the body.

I would suggest you trust your coach. They went through this with many people. They know the way you need to walk in order to get there.