The easiest way is to go to the Search Bar and type in "data"or "usage".
The circle is for "Search"
Then you can get to this screen:
Notice you can "View usage details". For me, this is what that page looks like:
By the way, I haven't made much a dent in my usage and I've been sick in bed and binge-watching tons of Youtube and Prime videos. My numbers, if accurate, really surprised me.
Before moving, I shared internet with family or I was with a familiar company local to Anchorage. Coming here and setting up internet limited me to 2 choices. One of those places was going to be a pain to use because of the way the apartment building is wired. I think I got a way better rate by going with Mediacom. (Not thrilled with their customer service, but...).
Of course, I can also sign into my Mediacom account and check usage, but it sure is nice to have backup numbers to compare with. If I start seeing huge discrepancies, then I will know to ask questions.
So, that's it. If any of you know how to check for different systems, be nice and share it with the rest of us.