The Release Notes and Installation Instructions for this plugin discuss where you can find the documentation : http://www.rsinc.com/down...61/relnotes_6_1h.txt ftp://ftp.rsinc.com/pub/idl_6.1_hdf5/relnotes_6_1h.txt "After the HDF5 plug-in has been installed, you can find documentation for the new features in the Adobe Acrobat file HDF5_Write_Support.pdf, located in the help subdirectory of your IDL 6.1 installation." If you do not find the "HDF5_Write_Support.pdf" file in the help/ subfolder of the IDL installation then I would try re-installing the HDF5 plugin.

From the IDL Online Help: Two example files that demonstrate the use of the HDF routines can be found in the examples/data_access/sdf subdirectory of the IDL distribution. The file hdf_info.pro prints a summary of basic information about an HDF file. The file hdf_rdwr.pro creates a new HDF file and then reads the information back from that file.