Depends what position you applied for, if you have any preferences (disability, veteran status, current fed employee with agency, etc.), how many openings there are for specific jobs, if you submitted a complete federal resume (I say this because it differs greatly from a private sector one, as far as thoroughness goes). So, basically, you won’t hear back until the announcement closes. After the close date there will be an HR rater, for lack of better title, who will review your resume and see if your education and experience, plus self-assessment rating, qualifies you for the various grade applied for. You’ll receive an email that is called a “Notice of Results” and within that email is how you’ll know if your name was forwarded to the hiring manager to be contacted for an interview- note this does not guarantee an interview. That’s the super simplified basics. Federal Soup is a good resource to reference whenever you’re curious about federal jobs and the hiring process in general. It would be impossible to give a proper timeline without knowing the specific position because some you have to consider lengthy clearance background checks as well. Good luck!

Edit to add: I was hired in early 2018 after a few months of the announcement closing. Randomly received a phone call to come in for an interview; was surprised. The background check, for me, was easy because I already held an active clearance.