This article will help you find your Segment write key.
First go to your Segment account and click sources, then Add Source button:
Enter in your JuniperWeb URL and whatever you want to name it, and click Add Source:
Go to the Settings button on the source page, enter in the info and Save Changes:
In the menu to the left, click on API keys and your write key will appear:
Once you have it, please log into Juniper Web, go to Settings > Integrations