Hello, and welcome! Sorry to hear about the wonkiness of jumping into a 3D modeling software, but I had the same behavior when I first started modeling. You do something you think is normal, but the program behaves unexpectedly. That’s okay! Don’t let that spook you. You’ll get it in no time.
Good effort on the sign. Maybe you could bevel some of the edges to help break up the “perfect” CG feel, like on the posts holding the sign. Keep pushing!
