These instructions explain how to open
sensu-slack-handler.json and edit the definition using Vi/Vim so you can complete the Learn Sensu sandbox Lesson #2, step 3.
NOTE: You can use any text editor you'd like for this step. These instructions are intended to help users who may not know how to open and edit the definition.
1. Open the JSON file.
2. Start "insert" mode so you can add and replace text.