When you register after installation,
There will be a blank for “Referral Code” in 'Register' page.
If you install True Balance from your friend’s invitation, copy the referral code and paste it into the blank.
After submitting the code, you will get the referral reward if you satisfy the requirements. (T&C Applied)
If you install the app without any referral code, you don’t need to insert anything during the registration process.