at the studio means I'm probably there working, possibly with a client. Either way, knock; if there's a moment, you're welcome to look around or grab a coffee if the machine is on. Sales are possible when time allows. open studio is a good moment for pickups or spontaneous visits. workshop ongoing means a class is running; brief visits or pickups are fine about half an hour before or after. studio sale marks fixed opening days for shopping, often with fresh pieces made especially for the occasion.