While some outreach and grassroots efforts are proving successful for small swaths of their communities, advocates still are struggling to navigate a dearth of vaccine doses and a generally chaotic system for securing them.

Thursday’s appointments for eligible residents in priority zip codes were still booked within seven minutes.

Need help navigating what some experts call the biggest mass vaccination campaign in history? Here’s a look at where to go and who to call for help.

The move comes as waitlists continue to balloon and local leaders plead for more help.