It can send exactly one person to any time and place in the entire lifespan of our universe. The person will stay at that time and place for exactly one hour and then return home. The machine works one time.
A few more rules:
Anything you can carry can be taken with you. Camera? Pen and paper? Firearm? Sure.
Likewise anything you can pick up and carry can be brought back with you if you like.
You are fully physically present on the other end of the trip. You can see, touch, and interact with your surroundings and vice versa while you are there. You speak whatever languages you speak when you enter the time machine.
Nevertheless, the time machine will protect you from death or serious physical harm. Conversely, you cannot permanently affect your destination. All physical effects you have and the memory of you will disappear the moment you return home. This isn’t a “kill baby Hitler” thing.
Finally, the time machine is omniscient. It has the ability to send you to a specific time and place (e.g. Pasadena, CA January 4, 2006), or to a specific event you describe (e.g. the first time a human being ever made fire, or the first time a human being sets foot an celestial body other than the earth or the moon).
Where you going Surly?