Hola Christopher
"Tened" is the imperative affirmative of "tener" for vosotros in this sentence in the lesson:
Tened cuidado cuando utilicéis el equipo de música.
Be careful when you use the stereo. [you=vosotros]
I'm aware that you chose Latin American focus so you would never be tested on the vosotros conjugations, however, the lessons that are standard lessons like this one have example sentences that apply both to Latam Spanish and European Spanish. We try to add extra notes like this that you find in this example "[you = vosotros]" to clarify the subject.
If you'd like to learn a bit about the imperative for vosotros, despite not having chosen European Spanish focus, here is a kwiziq lesson on the imperative for all verbs for the vosotros form.
Saludos
Inma
