I have the most up to date iPad version of SD (I’m on the 1 month trial), and when I click on notams with no route and tools the tutorial says I should see an “area brief” option instead of just narrow route, however I can’t see it. I can only see “proximity to route” and no option to switch to area. How come?

Because you haven't created an area to fly in yet (planned a route). Do as Mike says above, to either create a linear route, or a local flight.