Header white space

I am working with Storefront: https://store.hiker-bigtex.com/

As you can see the header white space is rather large and I would like:

The gaps between top of logo and top of page reduced.
Bottom of logo and menu reduced.
Bottom of menu and image reduced.

I am totally new to “coding” and added a child theme, then added the code recommended in this forum to allow adjustment but it totally crashed the site.

Is there a simple way to adjust the white space above?

I appreciate your assistance and have learned a lot from the forum already.

Paul