I’ve been seeing that Game Pass Ultimate members get the Pass Tense bundle? Anyone know where to claim this bundle? I have confirmed I am a Game Pass Ultimate member. I have checked the Windows Store, Xbox app on PC, and the in-game store and still have not found it. 
I’m not sure how on PC, but on Xbox, I started the Game Pass app, and went to perks. Look for the pack, and click it. Should take you to Halo Waypoint to redeem, if you are already logged in.
Xbox sent me a msg and in the msg is had "claim perks " to press.
As others have stated, go to the “Perks” section/tab and you can generate the code there to input here on Waypoint to unlock.
I was able to redeem it through the XBOX app on PC. I appreciate y’alls help!
Mine won’t even let me use it. I claimed it and everything on the right account but it hasn’t shown up for me on halo so I guess it’s impossible for me to obtain now that my gamepass code has been used… don’t mess up obtaining it! Or it’s gone forever, no nmistakes!