Quad safety

Hello, we have a 4 year old beagle and a 2 year beagle mix that we adopted 2 months ago their previous owner was a man that had them for hunting but doesn't seem that he had them on quad, so we are looking to train them to be on the quad, because we like to go for quad rides and go camping during the summer and would like to include the dogs in this.

My main question is what can I do to assure they don't jump off the bike, is there a certain leash harness or attachments I can use? They would be on a quad that has a seat on it. We also have a fish tub they would both fit in that had handles that could be used. We have two quads but my daughter is usually on with me so no room for the two of them.

Not looking for any hate just some helpful advice on how we can do this safely so they aren't jumping off the quad while we are driving.