An Arraiolos lesson should begin with the right vocabulary: these rugs are stitched on a ground, not woven on a loom.
The teacher can show how a design is transferred, how wool and canvas relate, and how the named stitch is formed. You make a short row, receive correction on tension or direction and repeat it. A small sample is a realistic outcome; a finished rug is not.
Museum or shop interpretation can add history and pattern knowledge. It does not provide tuition unless a practising embroiderer gives you materials, time and feedback. Ask who teaches and whether the session interrupts paid production.
The work is seated and repetitive, so lighting, hand comfort and pace matter. Arrange the visit before leaving Évora and treat it as the principal purpose of the half-day.