Need help please - Staffs

There are different ways depending on what you're going for. Normally, professional editors strive to get a balance between pages, so you don't have one page very full and another half empty. Som my main recommendation would be to add a page break after 7 or 8 systems so the pages are closer to the same fullness. The goal is both to keep consistent density on the page but also to avoid uneven margins.

If on the other hand you want the uneven margin for some reason, you can disable vertical spread in Format / Style / Page.