Welcome to the forum!

You are using a SMuFL font - right?

The quarter note symbol is a font character (in the SMuFL font) - and the half note symbol is another font character (in the SMuFL font).

To enter the half note character:

Text menu > Insert Symbol…

The dialog box Symbol Selection appears.

Go to the glyph category

Metronome marks

- and you will find the half note character.

Thank you for your message.

In the expression tool it says Engraver Text H font, not SMuFL.

I couldn't find glyph category in the Text Menu.

Any ideas?  Thank you!

… it says Engraver Text H font …

In that case the solution is simple (Expression Designer, main chiclet, select the Quarter Note character):

To enter a Whole Note, type lowercase w

To enter a Half Note, type lowercase h

To enter a Quarter Note, type lowercase q

To enter an Eighth Note, type lowercase e

This is all displayed in the Symbol Selection window where you can see the font’s characters.

When, in the Symbol Selection, a character is selected, its keystroke is displayed.

I hope that this is clear?

If not, ask again.

… I couldn't find glyph category in the Text Menu …

Glyph Categories are “SMuFL fonts only”.

Double-click on the expression, to go to the expression window, withTempo Marks. Click Create new tempo mark. In the next window, there is a dropdown for note value. Choose the half note, and enter your tempo as desired.

Thank you!!