I can't upload a specific image to Word Press

My website is https://www.nkscouting.com

I have taken a lot of photos, and there is one particular I want to use to start off my website. How do I go about getting a specific photo to start off my website.

I don’t mean a photo that will be inside the article. I mean to actually have one side-by-side photo with the intro paragraph about my various things.

Thanks