How to Create A 4 Column Grid that fills to the edge?

I am trying to make a 4 column grid like the one above with the shapes tool but it doesnt fill to the edge. If I make the shape bigger on the left and right they are not all uniform and the same size. How do I get a grid to look something like this photo above?

@helppls Would it be possible to share your site URL so I can take a look? Thanks!

Hello my website is here www.claraau.com its at the bottom of the homepage that i'm trying to make a 4 column grid. It doesn't fill to the edges and if I drag the right and left edges, they become uneven sizes

Add this to Custom CSS:

section[data-section-id="6503af7db155dc5e80c03592"] {
  .fluid-engine {
    --sqs-site-max-width:100vw;
    --sqs-site-gutter:0vw;
  }
}

It targets that one section using the top line, and sets the max width to the width of the screen. 

If you want to target more sections, you can find section IDs using this method:
https://squarefortytwo.com/squarespace-guides/find-an-id-in-squarespace-71

If you add a second section ID, put it after the first one, and separate them with a comma.