Carver Model 2866 Boattest How Do You Operate The Folding Handlebar On A BMW Slide Carver Scooter?

How do you operate the folding handlebar on a BMW Slide Carver scooter? - carver model 2866 boattest

I recently received a used BMW Slide Carver as a gift. It came with the handle when folded, with the key. I can not imagine how to unlock the handlebar in the raised position for use. You can take a picture of this model can be found in http://store.dickhorriganbmw.com/default.tpl?action=full&cart=109619667894018&--eqskudatarq=80930148787