Permalink Problem – How to get nested permalinks?

Hey, I am building a site using WP. I have a main packages page (example.com/pkg) which I want to link to pages for specific packages like example.com/pkg/pkg1 and example.com/pkg/coolpkg & so on… Whenever I try and add an extra slash to permalink editor, it just removes it & what i get is – example.com/pkgpkg1 How can I get nested permalinks? Thanks in advance