Harryyao,
Usually, to run an existing test case, you need for example, to be in the following folder :
C:\opentelemac-mascaret\v6p3\examples\telemac2d\bumpflu
Next, run the following command :
telemac2d.py t2d_bumpflu.cas
If you have used the automatic installer, you should run the command from the shortcut created by the installer.
If you succeed to run the test case the sentence "my work is done" will be displayed and the results will be in the same folder :
C:\opentelemac-mascaret\v6p3\examples\telemac2d\bumpflu
If you still have the error that telemac2d.py is not recognized as an internal or external command, would you type "path" in your DOS command and send the output to me ?
Hope this helps
Juliette