The following three videos show the techniques used at different herbaria for mounting plants. Many herbaria in this country and in New York use the same techniques but some of them may glue the specimens and some may use herbarium tape or stitching. Some may include a separate envelope and some may not. There are also slightly different sizes of herbarium mounting paper but they should all fit in a standard size herbarium cabinet. A lot of work goes into each specimen so handle them carefully. They will last over 100 years if preserved properly. Probably the biggest difference in the presentations is the accent of the presenters!
http://www.youtube.com/watch?v=RCEngXim6sg