Don't panic about how often you stir. You can figure this out as you go. Stirring creates more acid, which is what makes it into cheese, but you don't want too much acid. It's more of I did this this time and this is how it came out, so next time I might want to do that.
There is no way that a book can know what kind of milk you are using, or the temperature in the house, and so many other variables. It's not that precise.
Keep records of everything. Time, temperature, how much you stirred, if you are worried about it.
When you taste it, you can read your notes and then decide if you want to do something different.
Right now, you have cheese! And now you must age it.