A question about a recipe: Creamy Homemade Ricotta

I have a question about step 2 on the recipe "Creamy Homemade Ricotta" from Jennifer Perillo. It says:

"Once the curds begin to separate from the whey (you'll see little specks of white bob to the surface), stir gently and set heat to the lowest setting (see NOTE). Cook for 2 more minutes, then remove pot from heat and set on an unlit back burner for at least 30 minutes, and up to one hour. (this will help the curds further develop). "