1. Inline experiments will bucket and assign users, and fire the trackingCallback method. This is where you would add the segment track() method. Within the GrowthBook UI you would then have to create an experiment analysis to see the results of the experiment. The GrowthBook UI makes this pretty easy as it would see the new experiment data in your database, and prompt you to create it.
2. GrowthBook only fires the one trackingCallback event on experiment assignment (experiment viewed in the docs). You would need to add the Segment track event method there when you implement the SDK. All other events for other metrics your users do would also need to be tracked with Segment, and GrowthBook does not do this automatically.
3. You will need to tell GrowthBook SDK what the user ID is setting the user attributes (
https://docs.growthbook.io/lib/js#attributes). By default, GrowthBook assigns users based on the "id" but you can change this if you prefer to use another name/attribute by setting the "hashAttribute" in the inlineExperiment.