Where to get precise recipies?
For the beginner wanting explicit instructions, I don't think you can do better than a 14 day free trial of the America's Test Kitchen website. They break everything down to where it's almost foolproof (which can actually be a bit of a negative to highly experienced cooks); it's great if you're stepping outside of your comfort zone.

You can learn a LOT from that site in 14 days. Cancel within that window and you won't be charged. If you want one more month or simply to pay one month at a time instead of a 1 year lump payment, talk to customer service, they will accommodate.

Immediately upon free registration you will get access to some 14 or 15 seasons worth of videos, with accompanying recipes, taste tests and science lectures from the shows "America's Test Kitchen" and "Cook's Country", along with articles from the magazine, "Cook's Illustrated".

They're very highly regarded, and geared especially to help non-expert cooks not mess up.

This may sound a bit like a paid ad, but I assure you that it is not. My subscription paid up through the calendar year. I may or may not resubscribe, but I've totally gotten my money's worth so far.

EDIT I looked up your example. There are 2 recipes for basic stove-top polenta on the site. One says this:


  ... pour the cornmeal into the water in a very slow stream from a measuring cup, all the while whisking in a circular motion to prevent lumps.


and includes a 3 minute video straight from the television show demonstrating this recipe for polenta from beginning to end. In the video they cover the hows and whys of pouring the cornmeal in slowly while rapidly whisking in a circular motion and you see her actually doing that.

In the other recipe they use a wooden spoon.


  very slowly pour the polenta into the boiling liquid while stirring constantly in a circular motion with a wooden spoon (see the illustration below). 


 

They're like that with everything. If there is a way to screw up the recipe, they'll keep you from doing it. They'll also tell you what brands won their taste tests and their recommendations. I don't think for a second that they're willing to sell their influence. For polenta, they recommend: