Creating stemless note heads

You could use the list of note heads in the properties window but there's no
point because you can change the note head with keystrokes.

Shift+Equals and Shift+Dash cycle through all the various note heads.

You can also go straight to the right note head by holding Alt and Shift and
then typing the number quickly on the number row. E.G. holding Alt and Shift
and then tapping 1 twice quickly will give you note head 11. (Note head 0 is
the normal note head.)

7 is the stemless note head, so typing Alt+Shift+7 should get you what you
want.