Bungie gives certain cosmetics only $10 card that will unlocks as you play and complete the achievements. 

Get Spectral Pages by completing activities. 

Activies ranging from Strikes, Gambit, Crucible, Battlegrounds, etc..

Quickly complete the activities.

Put best practices to achieve "Spectral Pages" quickly.

I recommend you to not buy last season pass its not have enough good stuff in it.

The core gameplay of destiny 2 loop remain the same appearance.

Wear mask and collect candy to complete activities.

destiny 2 Latest Event Card has total 17 challenges to complete.

You can accomplish all challenges within next couple of weeks.