I have searched the web for this answer and everyone seems to have this same problem. Even if you align the masterhead to the left, the container is centered and has about a 70% screen width, so the content inside can't go any wider.
I have been thinking and this could be done by adding rich text maybe? but the template doesn't allow you to add one.
I am using the Thomas template and I know it can be done because of these 3 examples:
I'm not sure I explained myself very clearly. What I mean is that the container is centered to about 70% screen width and I would like to put my text to the left margin so it is square with the other elements of the page