Problem with header please help!

Hello everybody!
I’m new here. I have a problem - I want to make my header bigger and center it (now it is moved to the left). I have also problem with making bigger spaces between text lines and between text and photos. I’m new in Wordpress word - if I need to add some lines to source code please tell me how to do it. Thank You for your help!

My site is

I use Sydney theme

Thank You!