Mini Golf is an addictive little game app that demonstrates how to use the Fling, TouchUp and TouchDown gestures on Sprites. Hold down the positioning arrows to move the ball to the desired position on the tee, then Tee Off by flinging the ball toward the hole. After a hole is scored, the screen randomly sets up a new hole, providing a unique challenge every time. This tutorial is for App Inventor 2. apparently successfully and you 'made additions'. The additions could be the problem.
It may be that when you made the 'additions' you inadvertently changed the starting positions of the sprites or you may have changed the position of the Canvas. We do not know because you have not shared an image of your blocks or shown an image of how the spirtes initially line up versus how they are supposed to line up.
A guess is that your initial sprite positions as set in the Designer are aligned as you see at Project start and you need to adjust those coordinates.
Regards,
Steve