Sustaining A Note

Hi Musescore team,

How do I sustain a note when making a score? I'll need it to compose my "Super-Sized" arrangement; I'm having problems with this screenshot (provided below) and some comments on the internet told me about a "plugin" to add to musescore. I'm unsure what this "sustain plugin" is and can't find it in my inventory. Thanks!

• Arranger Team Universe