You can effectively copy an interval by making it the default for that type of interval. So for example if you have a particular set-up for warm ups then you can configure it for one warm up and then tap the "Make Default" button in the top right and the next time you create a warm up it will have the same duration, target, screen configuration etc.
It isn't quite a copy function but it does allow you to copy intervals (although it doesn't allow you to copy a whole group).
Thanks. Works great.