Different Voices, Same Note

What I have in mind is the first note in this score:

https://www.thisisclassicalguitar.com/wp-content/uploads/2023/04/Pratte…

Or, to put it differently, how can you do the first measure there in MuseScore? I can do the separate voices, but if I try to enter the first note in the upper voice (middle C on the first beat) then I have to enter it as an eighth note, which gives me an extra note there. Maybe the answer is not to enter the note, but somehow enter the stem and bar to connect it to the next eighth note?