Hello I am new here,
I am wondering how much time should I wait before i get my topic approved at music request?

and how would I know if its rejected of approved?

Hello I am new here,
1) I am wondering how much time should I wait before i get my topic approved at music request?

2) and how would I know if its rejected of approved?
1) It is not an automated process, you have to wait until an admin/moderator of the specific subforum sees the thread and approves it.

2) Well, for a start, your postcounter would increase if your thread(s) get approved.