In the Ultimate Team Menu you will see Complete Collections and it will lead you to a list of various collections you can try to achieve. Easiest is usually the weekly items as they usually just require low ranking/bronze players. Find the collection you can most easily complete and the achievement will unlock.
Note: Some people seem to have problems unlocking immediately. Once the collection is complete back out to the main menu, then go back in and it should pop.
Online note: EA is notorious for shutting down servers, if you have this game I’d recommend unlocking this achievement ASAP in order to ensure you’re not locked out of it.