Some one help me pls

For the last two hours, I've been trying to create a website, but I can't solve one problem with the header. First, I designed the header to fit on mobile, but when I tried to adjust the site for a desktop device, the navigation bar didn’t appear in the top right corner.
I’d really appreciate it if you could give me some suggestions to find a solution Btw I'm a beginner, so if something doesn’t make sense, you’ll know why.