adding songs to favorites in musescore app (pro)

I have a new tablet and I finally can now run the songbook on my tablet.
I uploaded all the scores I made in musescore on my desktop to the songbook and they are now all in 'mijn bladmuziek' (my sheetmusic) ... there are however songs that I play and songs I still have to learn.
I would like to put the songs I already know how to play in my favorites but it just does not work.
The help function says to tap the three dotted icon and press favorite ... but all I see when I do that is Share and download ...
No help from the help function so I turn to here for help!
Thanks in advance!