Below are the 4 steps to integrate Segment:
1. (Refer to the image below) Go to Settings >> Integrations >> Segment. After you click on "Enable Now", an API key will appear. Keep this API key handy:
2. Login to your Segment account & choose the destination as 'Factors'. More details around Factors as a Segment destination here. Though you don't need to refer to that doc for integration.
3. Copy the API Key available from Factors (step 1) & use it to enable Factors's integration inside Segment.
4. Enable all the data sources that you would like to integrate with Factors (Eg: Website Production data).