The Tuesday Meditations are guided meditations. We simply sit (and walk or move) in the presence of what is alive in and around us. They are not a Sensory Awareness class, though the approach is similar, a Sensory Awareness approach to insight meditation, usually a spontaneous improvisation on a theme requested by the participants. The general format is 20 minutes sitting / 10 minutes walking / 20 minutes sitting.
While the 50 minutes are a whole, you can also just stay for the first part until the walking and/or do the other parts at a different time.