Help please! Non expiernced Dad with creative daughter! Ender 3 v3 se

Printer is not completing, after setting up, the tester cat print came out great we did 3 of them 2 colors. Afterwards I finally figured out what a g code was and how to slice and export it to the sd card and now the prints are not completing. Please help I bought this for my 10 year creative personality child and figured I’d have to tinker with it but not sure what to do. I even tried the tester cat again and now that is not printing either. Just a dad trying my best.