This 12 week programme should only be started if you can already run 10k. It's progressive and structured to build and periodise over the 12 weeks.
Link your garmin or apple watch to training peaks to automatically load your workouts into the plan, and try to complete the first test as per the instructions. This will make the remaining plan much more specific to you.
As a GBR age-group sprint distance triathlete, I came into triathlon and competive sport fairly late in life (late 30s), starting with rowing and more latterly into triathlon.
I know what it takes to balance work, life and training, particularly for the more mature athletes! Taking time to rest and recover is a key aspect of my 1-1 coaching.