The Nokia website probably has a manual you can download.
Whoever provides your connection quite probably has a website with at least FAQ.
The connection provider likely has a "chat support" line where someone who knows both the phone and the service setup, and can look at your account if/when you give permission.
The problem most likely is with the account setup, and NOT particularly likely to be with the phone.
If it is the phone, you probably should take it back and demand a replacement, and also insist that the seller do the setup for you before you accept the new one. Although many sellers have limited abilities, they can call the provider (on their phone) and follow the instructions so that you don't have to pay cell phone rates while the support people fumble around with it.