To Divide or Sew Seeds?

You can do either. Sow the seeds fresh and push them back into the compost if the plumes pushn them out (or cut plumes off before sowing). They should germinate in 2 weeks and flower the following year. To divide the original plants, lift them and divide them into rooted pieces, each with a stem and some roots. Pot the pieces up in a sandy soil and don't bury the crown.

Personally I would recommend growing from seed. Pulsatilla's have a long tap root and if this is damaged they will not do well. Digging them up almost always breaks said tap root.