Ender 3V2 gcode issues

Hi i am a newbie and trying to get going on the Ender 3V2. Setup went fine and printed the dog without any issues. I have since being trying to print various files dowloaded from Thingiverse. Generating the Gcode via Cura and also the creality slicer. They just won't print. The status bar says they are printing and they go all the way to 100% but nothing happens. I have successfully managed to print 1 downloaded file from Thingiverse but thats probably 1 out of 10-15 files. I have also downloaded some of the files shown on youtube so i know they should work on the Ender 3. Help would be greatly appreciated as my 11yr old got this from Santa and all we have to show to date is a 1 inch dog :(.

Regards
Colm