How to Join a Server on Minecraft PE? And give me a better server too?

It does it automatically if you have version 1.7 or above. Or at least it does for me. From different devices and different providers too. Download the latest version from Istore or Google Play

Launch MCPE. Go to the top right corner and click on "Edit". Click on "External". Provide details such as the server name, IP address and port number. Click "Add Server". It should work. If not, just try multiple times until it does.

You can look for MCPE servers here: http://www.minecraftforum.net/...pe-servers. I don't know what type you're looking for, so I won't list any.