How to change header in child theme?

Hello, I am using a child theme under Simple Catch Pro. I want to make a few changes to the header content, to change H1 tags to H2 on logo and title, and to remove the H2 tag on slogan. Maybe also do some other minor changes. Could somebody please give me some guidance on how to achieve this? My website is at http://www.saf-org.no Thankful for assistance. Best regards, TJ Braatveit