If it is like the old typewriter lifts, you have to give it a little push first to make it go down, holding on to it as it goes. Once it is down, then push it in like a drawer. When you want to bring it up, pull it out, and holding on to it, bring it up.
I would put your machine on it and try it. Or take a box of books and try that. I would try and try. Or have someone help you with it. It is a treasure.