Create bitly application
Follow this tutorials to create new bitly application.
Step 1: Go to https://bitly.com/a/oauth_apps
Step 2: Click Register an application
Step 3: After provide your mail to get registration code, click Get Registration Code and check mail box for code.
Step 4: Check mail box and follow link form email, you will continue to setup your application.
Step 5: Get
If you have any question, tell us please, otherwise read next tutorial to get start with bitly login