To unlock this achievement, you have to complete a daily quest that is called "All Together Now" (thank you dieresis for confirming the exact name of the quest).
Every day at the same time (9 pm for me) you get a new daily quest that you can see on the quests tab of the main menu. These quests give 50 V-coins
and 20 Founder's Money (Founder's Money is no longer being used) as a reward for completing them, and you can have up to 3 active at the same time.
The one for this achievement is for completing 3 "Play With Others" quests. "Play With Others" quests are the quests you complete by searching for a match using the question mark that appears on the map.
This is what the daily quest it looks like on the Quests tab:
(the screenshot is not mine, I used the one at
https://freethevbucks.com/daily-quests/)
You can choose to search for a quick match or searching for matches that correspond to your story progression (it might take a it longer to find a match, depending on your progression).
Also, there might be some additional requirement (like purchasing a certain amount of skill tree nodes or story progression) or maybe the achievement is a bit bugged, because I got this same quest at the very beginning of the game (it was one of the first ones I got), and the achievement didin't unlock then. Now I'm in Plankerton and have purchased quite a bit of skill nodes and the achievement popped just fine.