What is a one-sentence summary of the following article?
Open WhatsApp. On the Your Phone Number screen, enter your phone number, and then touch Done.  If you're not in the United States, touch United States, and then select the country where you live. When you register, WhatsApp will send you an SMS message with a verification code. You'll need to enter this code before you can proceed. If you don't have SMS on your phone, you can also request an automated phone call. On the Profile screen, enter the name you'd like to use with WhatsApp, and then touch Done.  You can use your real name or a pseudonym. You can add a profile photo on this screen. WhatsApp will ask you for access to your phone's contacts. If you permit this, WhatsApp will use your contacts' phone numbers to search for WhatsApp users and then add them to favorites screen. It will list all of your contacts on the Contacts screen. If you choose not to permit this access, you can always add friends to WhatsApp manually using their phone numbers.

Summary:
Register an account. Enter your name. Find your friends on WhatsApp.