You can check your application status by going here. This will list all positions that you've applied to, and you can see your application status (under review, etc).
If you'd like to contact the hiring manager, you can do so here, by using the "chat" function.
Don't forget to go to interview requests (here) to see if any positions have invited you to interview.
If you don't see your application listed, try searching for it here. It may have been deleted/ filled already, if you aren't seeing it pop up in search results.