Once you got everything setup and working. Call your favorite US person, and ask them to make a phone call to you. You will want to test that you can receive a call. You would also want to test your voicemail service is working properly. Once you tested the incoming features, consider calling your favorite US person, and make sure they can receive calls, and hear you properly. If you are having problems, you would need to send a support ticket with Callcentric.
Once you are confident that everything is working fine, you can now provide this number to anyone that wants your US number. If you have your own website, I would recommend that you place the number on the contact page of your site unless you want the number to be private. If you want the number to be private, then just give the number to only those that you want them to have the number. Keep in mind, your international format for writing the number will be +1 and 10 digits following the +1. Usually people will place spaces or symbols after the 3rd and 6th digits, but this is just to make things simpler to read. ITU Standards implies for no spaces.