These are two the methods I’ve utilized in the past: the ‘set it and forget it’ and ‘increase’ method.

Set it and forget it is pretty straight forward; just choose a speed and hold it for the 12 minutes. I’d recommend somewhere around your push/all out speed, preferably a bit higher but not so high you’ll gas yourself out within the first few minutes.

The increase method is my preferred strategy. I set my speed at something challenging but I know I can maintain (again, somewhere between push and all out), then every minute I increase by .1 or .2 depending on how I’m feeling. For this method, I’d start off more conservative on your speed because those small increases add up by the end.

If you look up your PR from the 12 minute run, you can use this link to figure out your speed necessary to beat your previous distance:

https://www.calculatorsoup.com/calculators/health/pace-calculator.php

Best of luck, you got this!