Instructions for a stove top pressure cooker?

For a stove top pressure cooker, it means just as the pressure cooker starts the first whistle. It should take about 5 tp 7 minus on medium high heat for the amount of ingredients in the recipe for the pressure cooker to fully pressurize.

Although I'm an Instant Pot fan, there are some recipes where it isn't necessary. This, in my opinion, is one of those. The 1 minute pressure time is used for frozen spinach, and the 0 time is for fresh. Essentially, if you are using fresh spinach, you won't need to pressure cook it at all. That's how I'd interpret the 0 minute direction. Spinach cooks very quickly, though obviously frozen would need a bit more heat. I would simply thaw the frozen product if I could not use fresh. The residual heat should be enough to wilt and cook it, without the need for pressure. Truthfully, I don't think it's really necessary to make this in any kind of pressure cooker, electric or stovetop. A nice heavy saucepan will do just fine. Spinach isn't quite the same as a chuck roast, and doesn't require hours to cook, like a stew or beans. I have no idea why it would be used for this recipe, and can't see a reason to do so.