i can see paytm code at the merchant store how can i make payment using paytm code

I can see Paytm code at the merchant store, how can I make payment using Paytm code?

Open the Paytm App.
Tap on Pay or Send icon.
Your camera will open to scan the merchant code
Scan the merchant code
You can mention the reason for sending money. This field is optional.
Enter the amount and tap Pay
If you have sufficient balance in your Paytm wallet, money will be successfully paid.
If you do not have sufficient balance, you will be redirected to the payment details page, where you can add money in your Paytm wallet and then pay.
Confirmation SMS will be sent to you and merchant