As a new member
no contribution, you can not get acceptance to change your username, in most of cases. So as other members told you, let's move on with a new account. Exception is if your current username contains something that can be used to dox you later.
Done. Now only moderators, Donators, and VIP members can change their names automatically. Other members should contact me. I'll probably ignore your request if you have less than 50 posts (unless your posts are very good).
You can't. You can try PM an admin and they may do it, but they usually don't. You can just create another account with that name if you feel like you need it.
Sometimes theymos will accept request from members to change usernames but it won't be approved too commonly.