I have been using the trial version for a couple of days and am trying to find the notation for string tremolando, drum roll etc. - in other words three strokes through the stem. I searched through on-line help and so on, but cannot find out how to achieve it. Could someone point me in the right direction, please?

You will find tremolos in the ‘Repeat Structures’ panel on the right (look for the symbol of a repeat ending).

This page in the online manual talks about tremolos, and the links at the bottom help you with inputting single-note or multiple-note tremolos:

One thing not yet updated in the documentation is some of the easier functionality of the popover.

Shift-R for the repeat popover. Enter 1, 2, 3, etc for the number of tremolo slashes you want.

To remove a tremolo, Shift-R, 0.

Thanks for the information. I did find the solution before this post was approved (by searching on tremolo instead of tremolando) but the extra hints you have provided are very useful.