Newbie basic problem with Menu

Hi Guys

I’m think I’m still having some basic problems I’ve not come across before, and would value some assistance please.

I’m building the site above, and am having a problem with the menu. Where I have sub menu’s, I don’t want the menu top line text to refer to a page, just the sub menu items. However I don’t seem to be able to get it to operate correctly – how do I create a situation where (when there is a sub menu) the main menu text doesn’t try to link to a page, which it appears to do at present?
Also, sometimes when I try to drop down from the main menu to the sub menu, the sub menu list disappears.

I expect I’ve missed something basic, but all advice would be welcome.

I’m using GeneratePress Premium with Elementor.

The page I need help with: [log in to see the link]