Guitar glissandos

Hello,

I have an old computer running W7 and I can't afford to upgrade to W10 or W11
at the moment. Here is the description: - OS: Windows 7 SP 1 (6.1), Arch.: x86_64,
MuseScore version (64-bit): 3.0.0.4787, revision: c1a5e4c

My instrument, which I play as an amateur, is the classical guitar. I tried, without really
succeeding, to create “glissandos” of individual or multiple notes. The display on the
staff and on the tablature show the glisendo but when I play the sounds, instead of
hearing the note increase or decrease to the next note, I hear the string, or strings,
being plucked twice as if there was no sign of glissando.

1- How to create these glissandos sounds, please?

2- In addition, as illustrated in the image, when I try to create
glissandos for several notes, I cannot separate each of the notes. Glissandos regroup
and all point to the next highest note.

(Image)

THANKS.

Daniel Dion