I would try it on whatever tripod you have to start out with. If your results are unsatisfactory then you can invest in a new camera plate. In some time you'll end up with about a billion little film boxes in which to store exposed but unprocessed negatives but for now just store those under the bag containing unexposed film. You might want to keep the box taped shut just to avoid a bit of light leak since the film isn't in the bags.

To expose film you focus and compose on the groundglass (a darkcloth/loupe helps for this...any kind will do). then CLOSE THE LENS!, stop the aperture down and set the shutter speed. insert your film holder in the back, remove the darkslide, fire the shutter, and re-insert the darkslide. Be sure to flip the darkslide so you know which negative you've exposed.

If I've missed something I'm sure someone will let you know; you do this so often it becomes a routine.