Can that battery even power those motors in the first place? Try connecting your battery directly to one, see what happens.
Check your battery - if they can power the motors at all it will be for a really short time. A few minutes or so. So you may have drained them already. Mind that you lose an additional 2-3V on the L298N, so your motors get 6-7V at most (check the data sheet for exact numbers).
Same for the Arduino. Upload will go fine as then it's powered by the USB port. That battery should last a few hours but it may very well be empty, too.
Use a proper power supply for your testing (9-12V wall wart). Then you can connect the Arduino to the same power supply as the rest.
Make sure the grounds are shared.
Oh, and learn to draw circuit diagrams. For that, start by ditching Fritzing and installing proper circuit software such as KiCAD or EagleCAD (or just do it by hand on paper, your circuit is simple enough).