Atomic Mass Games Star Wars: X-Wing (2nd Ed.) - Accessories - Maneuver Dial - Separatist Alliance

Q: Can you use this to start playing or do you need to get the core set first?

You need the core set for movement templates and a damage deck, at least until Feb 2020. FFG plans to release standalone damage decks around that time. And if you don’t mind going third party, there are other movement templates available now separate from the core set.