Not a stupid question at all

A very common one actually.
If you have a meeting with them, you sit down, tell them the title and genre, give them your one-line pitch. They usually ask questions at this point, and you can go into more detail about what your book is about. It's pretty much the same setup as your query hook, though remember that speaking a line and reading a line are very different. Some lines read fine on paper but are awkward out loud, so practice what you're going to say.
If you want to pitch editors at random...
Remember they get attacked on a regular basis. Be friendly, strike up a conversation, don't assume they want or have time to hear you right then and there. Mention you'd love a chance to pitch your novel if they have time. Sometimes they'll ask about the book, other times they'll gracefully bow out. They're time is pretty booked at a lo/t of these things, so be considerate.
Above all, be friendly, be professional, be brief. Sharpen your one-line pitch to a razor point. Perhaps something like "I have this (genre) novel about ... short one line hook, would you have time to talk sometime this (length of conference)?" Give them an out if they aren't interested. Give them a reason to
be interested with the hook.
And don't corner them in a bathroom

It's just tacky.