Your question is a little backwards, to be honest.
When you start doing darkroom work, it's best to follow methods recommended by manufacturers of film and chemicals. For fairly standard film developing, widely accepted standards hold that 5 seconds every 30 seconds, or 10 seconds every minute is good practice.
A few dozen rolls into developing and printing your film you will start to see how developing time affects your results, so if you have a very high contrast scene that you photograph, and you develop normally, you may block up the highlights so badly that when you try to print the negatives you can't get any detail in the highlights. That means you need to shorten development time a little bit.
You may also find that when you print your negatives that it's difficult to get good separation in the mid-tones, because your negative is such low contrast that not even a high contrast filter helps you get both good blacks and good highlights. This means you need to lengthen your development time.
Then you'll start to notice that if you have poor shadow detail in high contrast scenarios you did not give your film enough exposure. So you learn to give more exposure in those situations. But then when you develop your film normally, the extra exposure means you have great shadow details, but the rest of the tones are so dense that you can't print through the highlights to get good detail in them.
So, now you're at the stage where you see a relationship between contrast in the light you photographed, how much exposure you must give to capture a full range of tones, and how you must compensate for this by developing a bit less time, in order to get a good printable negative.
Conversely, you'll also notice that when you have low contrast scenarios, like fog for example, it's not a bad idea to give a little bit less exposure, to spread out your shadow tones so that they don't print like middle gray, and then develop longer to expand your highlights, so that you get nice crisp whites in your prints.
And NOW, but not until NOW, is it really time to worry about agitation. Agitation is, compared to developing time, a fairly small adjustment to make. But it takes some good practice, with lots of printing, while learning the basic film developing rules, before you're even likely to notice much difference in agitation patterns.
So if it's the first time you use this film, along with a new developer, then I suggest to sticking to ten seconds every minute, while agitating continuously for maybe the first 30 seconds.
