Creating a new page

I’ve created a new page called Main and it sits along the top in a tabbed like fashion

The page Main is empty, wheb I click Main, I want it to open a broswer link. Is this possible, if so how?

When I hoover over the Main page it says https://www.domainname.com/?page_id=123. Instead of opening page 123 how do I get it to open a link

Thanks for any info