Theme Twenty Seventeen – Make Margins Smaller So That Text is Wider

I’m sure this is a very common question so I apologize in advance if this annoys some people.

This is my first ever blog so I have little to absolutely no knowledge on how to manipulate the elements to my liking.

The text in the blog uses about a third of the actual sites size and leaves a lot of empty space.

I would like this to use about 75% of the websites size. Attached is a image to give an idea of what is currently going on.

If you are going to tell me to use any form of coding, could you please include how I go about inserting said code into the website as again, super new here.

Thank you so much for anyone that is available to help.enter image description here