Take a cutting of firm new growth apply 0.1% IBA stick in well drained soil & mist taking 15-40 days to root... bottom heat helpful...

This plant easily rots under propagation with too much mist and/or humidity. Keep the foliage as dry as possilbe, especially overnight, and a little wilt during the day won't hurt it.

Silver Mound really should be divided every third year as it tends to 'brown out' in the center if left undivided. I would not waste my time propagating it from cuttings. Rather, dig a clump in the early spring and divide it in as many sections as you wish and replant. It will form new clumps quickly.