Hello.Try making the header height smaller than the background height of the header.

I need to achieve the result inside the main page so that it looks like in the foreground?

Then you need to write CSS styles.Please give a link to a page on your site.I will try to help you.

Insert the desired picture in png format, if the rest of the background should be transparent, in the stripes style, align to the desired edge and you're done.