Welcome clnpl, I use soft ties around the forks with racket straps and collapse the front forks using the rachets on the straps, meaning pull the front end down with the straps so when you hit a bump the front end does not bounce so the straps don't come undone.
Do not hook the strapes to the handlebars. Do you have a front wheel chulk on your trailer? If not make sure your front straps are angled foward and rear straps are angled backwards. The whole thing is pretty much common sense but a few tips can help, you don't want to learn anything the hard way when your scoots involved. Did any of this make any sense?