I would go back in time to the point where the person building the time machine got the idea, and tell him to build two, one smaller than the other to fit inside, and I would stand inside the smaller one. Think Russian dolls, but with more time travel. Then, I would have the bigger time machine go back in time to any point, and have the smaller one go forward in time the same distance. Just to see what would happen.
OR
I would have two time machines of the same size, shape, everything, and have a friend go forward in time on a platform where I could calculate the exact location of where it was. Then I would set up the other one and go back in time to before any of this happens. Then both me and my friend would go forward and back in time respectively to the point that both of us would be in the same place at the same time. Once again, just to see what would happen.
...
OR
I could go back in to whne Hitler was going to be born, and artificially inceminate his mother with a twin Hitler, and steal that one secretly at birth, raising him to be the exact opposite of what Hitler would become, and use my time travelling shenanigans to randomly switch the two out at random times iunder the pretext that he's got a personality disorder.
OR
I could do nothing with it, keeping it in my foyer as a conversation piece.