This is a story related achievement that can be obtained in Chapter 3 during the main quest to gather allies. I will try to be as spoiler free as possible. Save before approaching any potential ally as gaining support of some exclude others and acquiring 3 ends the quest.
Go speak to Dondalo in Noctis. My relationship with Noctis was "Friendly" and he was more than happy to help. Aligning yourself with the Vory might exlcude you from gaining his support.