After activating the SIM, you will have to insert the Jio SIM in the JioPhone. For the first month, your first recharge (FRC) of ₹125 will remain active and thereafter, on the 28th day first Unlimited Plan will be provided automatically.
This process will repeat every 28th day for 11 more recharge cycles. Just that, you will have to keep using the Jio SIM in the same JioPhone for the entire year to keep getting the benefits.