Code injection header laying on page content instead of above

Site URL: https://abigailbrockamp1.squarespace.com/

Hello! I am pretty much spanking brand new at coding so sometimes I don't even know how to properly search something. Hence my question here! I'm in a class right now and one of the assignments is to recreate an existing non-Squarespace site as a Squarespace. 

I went in and created an html table through the header code injection. However, I'm looking to make the header lay on top of pages (just like putting the header elements in the "bottom" sections of the site-styles) instead of above each page like a banner. 

I've uploaded a screenshot of my site header, and the original sites. Thanks so much!

Website: https://abigailbrockamp1.squarespace.com/

pw: brineintopedro

^^(possible B instead of b)