It seems that you tried to use one of our demo content and build your website on that.
The blue thing you see is actually is the background image of the first section on that page. Go to the Cornerstone and click on the Section magnifying glass icon to reveal the options. You will see an option for the background image. Currently, an image is set there, just remove that image.
The second issue is how you set the top sticky header. Go to X > Launch > Options > Header and set the Navbar top height properly to fix the issue:
Also, you will see other options there to fine tune your logo and header stuff.
I suggest that you check our knowledge base and get familiar with the options of our theme to know the details of how things are done:
Finally, kindly open up separate new threads for additional questions, to follow up the same question you are welcomed to reply here.