Hola DaveDingal: "you (informal) lower the volume!" = "¡baja el volumen!"........."you (formal) lower the volume!" = "baje el volumen" or "baje Usted el volumen". BTW, even though this looks like subjunctive, it really isn't, it is the imperative form of the verb. CHAU
Why does it just say "descend"? When i look at it I can see that saying " descend " doesn't really make sense but they should at least explain maybe something else. Is this really the way you would say it spanish ?