Download and install the app - Cult.fit Health Fitness & Gyms
Sign up or log in to the app
Go on the profile
Select the option - Referrals & Vouchers - Redeem Voucher
Kindly enter the voucher code received in "Enter Voucher code here"
Click on "Check Validity" to redeem the voucher
Press “redeem now” on the next screen
Refer here for the video: link