Part of the training explains how easy it is to reorder cards and fields on forms by dragging and dropping. What's a bit counter-productive with this feature is that the cards can swap places on their own.
Therefore, please lock the order of the card/field whenever we drag and drop it to somewhere (to respect the designers instructions, and to raise the value of the drag & drop).

https://powerapps.microsoft.com/en-us/guided-learning/learning-create-first-app-powerapps/
Thank you.