//For complete examples and data files, please go to https://github.com/groupdocsmetadata/GroupDocs_Metadata_NET
// initialize GifFormat
GifFormat GifFormat = new GifFormat(Common.MapSourceFilePath(filePath));
// get access to PagedText schema
var package = GifFormat.XmpValues.Schemes.PagedText;
// update MaxPageSize
package.MaxPageSize = new Dimensions(600, 800);
// update number of pages
package.NumberOfPages = 10;
// update plate names
package.PlateNames = new string[] { "1", "2", "3" };
// commit changes
GifFormat.Save(Common.MapDestinationFilePath(filePath));