From the news post

Complete at least one Vanguard Request every day from Tuesday, February 4 to Saturday, February 22 and you can claim useful items. (To receive all items, you must complete a request every day of the event).

• Day 1: Valkyon Health Potion ×50
• Day 2: Traveler’s Insurance ×20
• Day 3: Canephora Potion ×10
• Day 4: Rare Noctenium Elixir ×20
• Day 5: Lamb Bulgogi ×20
• Day 6: Feast ×20
• Day 7: Additional Character Slot ×1
• Day 8: Bravery Potion ×20
• Day 9: Golden Plate ×300
• Day 10: Silver Plate ×75
• Day 11: Heart Shades (30 Day) ×1
• Day 12: Pure Refined Duranium Ore ×15
• Day 13: Azart Force Sign ×30
• Day 14: Azart Token ×30
• Day 15: Lein’s Dark Root Beer ×40
• Day 16: Firework (Heart) ×2
• Day 17: Firework (Heart) ×2
• Day 18: Firework (Heart) ×2

Note, it looks like you only need to login to claim the reward. No need to complete a vanguard request.