Adding lyrics

I’m still using the test version… It’s not easy to find the way without a helpful manual… Anyway I have a strange issue:

I have a score for voice an piano (from the template). Now I would like to add lyrics, but this is impossible. When I select the menu nothing happens, when I Press SHIFZ-L I get a short beep. That’s all. What can here be wrong?

Manual: https://www.steinberg.net/forums/viewtopic.php?f=246&t=129376

You need to be in write mode. Select a note, press Shift-L. The popover should appear?