Question #1 what will I see with my new telescope?
For astronomy telescope, the most important factor is aperture.
The more light you get to the eyepiece, it is the better. How this light is then used to create an image will also determine what you can see.
Fortunately most telescopes come with a reasonable eyepiece or two these days so you can atleast make out the moons around Jupiter if your eyesight is good in low light [Another factor not to be forgotten about in astronomy].
Even if you have a relatively inexpensive telescope you can always improve your viewing experience by upgrading to a higher quality eyepiece.
Steadiness of your tripod and mount, seeing conditions, your location (city or rural), brightness of the object and your experience are also important. You won't be able to see the American flag on the surface of the moon or black holes. You won't see as much colour as you see in astrophotographs (photos of celestial objects) because these utilize long exposure times which allow the light and color to build up on the film.