In order to verify your YouTube account, you must first go to YouTube and click to get your account verified. You will be required to provide a phone number for the account that you may have. The verification code will be sent through your account. The moment that you have verified your account, you will have the ability to upload videos that are more than 15 minutes long.
You can actually verify your account upon signing up. If you have not received the code through your phone immediately, you can check if your country actually supports getting text messages from Google. If this is the case, the voice call option will allow you to verify your account.