What Is Pocket Realms?
Pocket Realms is a server hosting community for Minecraft PE which alllows players to create small servers with up to ten people from anywhere in the world. So far it is in Beta so only selected people qualify for servers. That will be changed around the time PE leaves Alpha and goes into Infdev.
When you purchase your Realm (or server) you will immediatly have full control over it. You decide the name, seed, and gamemode of the server you will be creating. Upon creation you have your Server Dashboard. On the dashboard you can decide who you want to whitelist (add people), to turn the server off or on, and much more detais that will be added soon. When creating the server you wil be able to invite you friends to join any time even if you are not on. Within the server you get a normal world. You will be able to chat with the other people on your server which will help you be able to build things easier or just chat a bit.
How Do I Join Realms?
Evven though Realms isn't fully done you can still join it for future usage. Just click "Play On Realms" on the menu then select "Login/Sign Up). Then click sign up, fill out the info then your done.