How can I improve my website's header and background design?

[OfficialPrey]

Hey all! here is my website which i need a lot of feedback on, so first things first, if you know how to code and stuff with css or HTML, please add my discord Official Prey#0001 , second, my website 

rose-of-apparel.myshopify.com

Ok, so first my header, there are two pictures below, one with the transparent header and then second with the white background header and black icons, so for the white header, i want to make my white logo in the other photo to change to black to get to show in the middle of the white header as black, how?


Second, i want to make my banner or background full to take all the space when people land on the page, as you can see here, there is a huge white space, i want to make my photo much bigger to take the whole first page.