To install this special plugin you have to do a few steps more (after the installation of the extension itself (see above)):
Select the root TS Template by choosing Web>Template and clicking on “root”
Press “Click here to edit full record”
Move down to section Plugin
Locate “HTL Stundenplan (htl_stunden_raum_plan)” and click it
Enter the path where you can find the readable file
Save the record.
Press “Clear All Cache”.
Ok, done!