A low-fire silver 'clay', PMC3 can be fired with a hand-held butane micro-torch (like a creme brulee torch), or in a jewellery kiln.  As I sell my work, and want to be sure the silver particles in the clay are 'sintered' together as well as possible, I usually fire my pieces in one of the jewellery school's three kilns, for around two hours at 900 degrees centigrade.

It's perfectly possible to fire most PMC3 or Art Clay silver jewellery at home with a butane torch, though:  don't try to hand-fire rings or pieces larger or thicker than a 50p piece, and ensure you keep your piece at sintering temperature for at least 3 minutes (5 minutes is wise for larger or thicker pieces).

If you're feeling underconfident about firing your silver clay at home, the following Sussex Jewellery School courses teach you everything you need to know to fire silver clay safely and successfully:
Beginnings in Silver (1-day course)
Silver Jewellery Intensive (2-day course)