How to enable a Salesforce user as Live Chat Agent provided snap-ins are being used

*Assuming you are system admin and know about live chat configuration.

1. On user record, make sure checkbox are checked: Service Console User & Live Agent User.
2. Add user in queue which is associated with Live Chat button & Routing Configuration.
3. Add user in presence configuration (Setup → Presence Configuration)
4. On User profile (or any assigned permission set), add all available presence status in related list: Enabled Service Presence Status Access

Now all set! Ask user to login in salesforce, go to service console and make yourself available for chat!