Adding second image in header!

Hi all!

I’m trying to put some custom images in my header, but don’t know what code I must put in my header.php or add some to CSS! (and I’m not master in coding btw..)

https://postimg.org/image/b3p3yn6wt/

As it shown on picture above, my logo is on my left side, main menu on the right (top), so I want to put some pictures (three small pictures) bellow main menu (in that red rectangle) positioned on the right edge..

What exactly I need to add in header.php and where?
Sincerely,
Ante