Personalize a homepage

Hello fellow friends,

I came here to solicit your help. I installed a simple theme “hatch”. It works very well. When the homepage is configured displaying all my post (www.jeromevanbaelinghem.com/1.jpg) everything is fine. I would like to use a static page but here comes the problem. When I do, my content appeared to be locked in the small box next to the header (www.jeromevanbaelinghem.com/2.jpg). I looked in the code but wasn’t able to find the part I should modify to have a regular page.
Would you be nice to help me?

I thank you in advance ??

The page I need help with: [log in to see the link]