Could we see a screenshot of your workspace and the comp viewer before and after?
What camera are you looking at your comp through?
Also, what version of AE? 11.0.4? 12.2.0?
Show a screenshot of your Composition panel and Timeline panel.
You are not in the "active camera" view, but one of the auxiliary other 3D views.
Mylenium beat me to it. After Effects is NOT a program that you can just open and start using without going through the basics. Adobe TV has this great getting started video that will get you started with 3 of the things you need to know to be successful. There are hundreds of things to learn before you can be efficient and thousands before you can be proficient.