I'm looking at the Massive Dev Chart website. It shows a table like this:
Does the time shown there include the agitation time?
Agitation time is included in the development time.
Assuming you are using a small tank (this type seems to be the most common) the agitation is by inversion.
You start your timer, pour the developer in, seal the lid tightly, tap it to your table forcefully (to let the bubbles go) and then proceed to invert the tank for the first 30 seconds. Then invert 3 or 4 times on each minute.
If you like the Massive Dev Chart you will love the Massive Dev Chart Timer app. It has all the times + audible timer. I found that very helpful.
As always: if in doubt consult the film datasheet - https://www.ilfordphoto.com/amfile/file/download/file/1903/product/694/ - it will give you a good baseline for your process to build upon.