Complete the quest “Movie Night: Getting Started” from Liam, then “Movie Night: Snacks” from Suvi, then, after you visit (and subsequently leave) Kadara Port for the first time (during “Hunting the Archon”) you’ll be able to talk to Vetra, who will give you this quest. It’s incredibly simple, just head down to Kadara Port and buy some SNACKS from the Mod Merchant in Kadara Merchant. It’ll only set you back ten credits. Afterwards, return to Vetra on the Tempest to complete this quest.