How does one go about getting into the Archives to see {group 109} registry of patients in the Way Hospital from Jan 7 thru April 1, 1865.??

My Great-grandfather's roll call showed he was in the Hospital on Feb 11, 1865 in Meridian MS medical card#5211776 {complaint} Wounded. I would
like to learn more about the location of the Hospital in Meridian and get verification......
.