How do I make the Image banner cover the whole screen?

[LDLC_Shop]

I want the image banner of my website to cover even the header part when someone enters the store similarly to

here: 

And then when they scroll or hover over the menu, it turns back to the default color like this, and I also want the text color to change to white (I want to be able to edit this later on what color it changes to and back):

How do I make this possible?

Website: longdistanceloveclub.com

Password: edimar123

Thank you for any help in advance, also I hope its not too much to ask for!

[DarylMaguire95]

Interested also

[dcwcdw34]

Now I also want to do the same for my website, It is looking really cool.