You are able to move your troops after you beat a certain stage. I am not sure if it's stage 15 or 20. Click on Authority > Basic Management > and it should be the second option after Auto Battle. Hope this helps!
There was a bug in the prior version that prevented this the developer has since fixed. Which is already in the prior comments. Specifically, I was able to move their starting positions of units at first and only later couldn't move them.
