You need to go to this link -https://www.nvidia.com/en-us/geforce/campaigns/battlefield-v/
Then scroll right to the bottom and its in the middle above the Dice logo
EDIT - Here's the text
REDEMPTION INSTRUCTIONS
To redeem your promotional code for Battlefield™ V, please follow the steps below:
1.To begin the process to redeem your award, please click here.
2.Please sign in to access the redemption system.
3.Paste your coupon code from your qualifying bundle purchase into the "ENTER YOUR PROMO CODE" box. Characters are case sensitive.
4.Enter the validation text into the "ENTER THE TEXT" box and click "REDEEM".
5.Click on the Log-in button to sign-in to Origin.
6.Enter the appropriate information to sign-in to your Origin...