To be able to dig deeper into your numbers you need to start sending to June some information about your users. This information can be their email, their name, the plan they're on, or any other information you might find useful to analyze.
The way you send to June information about who your users are is by sending an identify call.
This call will require a unique userId and some traits. Traits are all attributes you want your users to have in June.
Here's an example of what an identify call looks like:
userId: "2345678", // A unique and never changing user id of your user (avoid using emails here as they sometimes change)
plan: "Pro", // Add here any attributes you want to use in your analyis
email: "[email protected]", // Make sure you include your users' email
favorite_car: "Fiat" // You can add whatever you want here
Depending on the programming language you use the exact syntax you'll use will change.
If you have more questions you can look into Segment's official documentation