It's not a product I use, and I am more an L&P girl, but the main principles are the same no matter the system.
If your product touches the skin at the sidewalls during application, then it will not be properly adhered to the nail plate, and will lift.
If your form isn't properly fitted when applying the product will not properly adhere to the nail plate at the tops and sides of the nail, and will lift.
You have just finished training so these are typical rookie errors lol, we all have been there.
You need to work on your application skills a d your finish filing.
It would be easier to see for us to pinpoint what was going wrong if it was just a natural,set of enhancements, the colour coats and nail art cover over any flaws like lifting.