Vertical (small end down) is nice if you have a means of turning them so the yolk can be kept centered. If not (as in a turner or tilted egg cartons) then laying on the side is better so they can better be turned by hand.
Glad you could join the flock! Here is an excellent article on incubating ~ https://www.backyardchickens.com/a/hatching-eggs-101
Lots of great info to read in it. For me I don't wash or sand paper any eggs prior to incubation. Doing this can remove the bloom which keeps bacteria out of the egg. Removing the bloom could allow bacteria to affect the developing embryo. I only incubate clean unsoiled eggs.
Good luck with your future incubations amd enjoy BYC