how to make this header with borders

Hi there,

I would suggest using this method here to get that layout of the example site: https://docs.generatepress.com/article/navigation-logo/#navigation-as-header

Then you will need this CSS for the border:

.main-navigation {
    border-bottom: 2px solid #000;
}

thank you very much
now how can I put social network icons next to the main navigation primary

This might help: https://docs.generatepress.com/article/adding-icons-to-menu-items/

thank you very much

No problem :)