Python kivy add_widget adds double the amount of widget that overlap on each other

I was working on the pong tutorial provided by the Kivy documentation website, after making the .kv file where I implemented the centered rectangle, and the numbers(labels), I ran the code, but the screen was just black. I have looked all over youtube, and asked chatGPT, but cannot find the source of my issue. The code:

My English Crash Course program requires that the user navigate to the next/previous first and last record until the end
of the table by clicking buttons that say move next/previous last/first. this code always bring the first

I am trying to execute a function on button press. I tried different method
found on tutorials but with no avail, it gives the following error

I just started using kivy to make apps with python, and I am creating a kivy comic maker where you need to drag items onto the screen. However, when I try to when running, I can’t move the image needing to be dragged. I have tried many things to solve this issue, but nothing works. I want the draggable image to be in a scrollable library of images, but I can’t even drag it in the first place.

I am trying to make a stopwatch on a screen but i keep getting this error:
82: Label:
83: id: timer

I’m some what new to Kivy / KivyMD and struggling with a time issue of some sort.