L293D motor Driver

Hello there, I am currently using a single L293D motor Driver to control 2 12v DC motors. I am planning on using my setup in an RC Vehicle however the 5v supplied from my arduino is too low. I am planning on using a 12v power supply then with a LM7805 voltage regulator step down the voltage to my Nano to 5v. but here is my question.

I have been told that the L293D can support up to 36v on pin 16 and pin 8

But I am worried to test this as I am not totally 100% sure which wire from my 12V power supply goes where.

As in do I use VCC 1 or VCC 2 for the power to motors.

I assume that Positive lead (Red) goes to the VCC 1 or should it be VCC 2?, and Black to ground but which ground to use in this case? does it matter?

Vcc1 gets 5v for logic supply. Vcc2 gets the motor voltage.

All of the ground pins are internally connected. They are used partly for heatsinking (they're all meant to be soldered to the ground plane of the PCB, so the PCB will act as a heatsink) - if you're doing this without a PCB (ie, on breadboard or prototyping board) you may not be able to get the full spec'ed current without additional cooling.

This is all explained in the datasheet....

I am not noticing much of a drop in current however when I attach my LM7805 and try to power my nano with the 5v from that and the rest of the 12V going to the VCC2 pin my current drops to the point my nano barely runs and the LM7805 heats up to super high temps(using a 1.5x1.5" heatsink

Please post a clear and complete schematic.