Printing procedures vary depending on which software you used and where you are printing your poster.
The following are good options for printing:
https://aux-services.unc.edu/printing/
You can pick up your poster from this reasonably priced online service on campus or have it delivered to your location.
https://www.spoonflower.com/presentation-posters
https://www.fedex.com/en-us/printing/online-printing.html
Additionally, your school or department may offer poster printing services. Contact them for details.