If it is making more plants your after, you should take basal cuttings, i.e young new shoots, when they are about 2 inches in early spring, as the first leaves come out. Cut them from as close to the base as possible with a bit of older woody tissue. Then cut the bottom straight, remove leaves from the first third and put in a standard cuttings compost after dipping in hormone powder.
When the begonia tubers show sign of pink bud growth,cut into sections, each with at least 2 buds. Dip the cut ends in yellow sulphur powder to prevent rotting and infection.Plant each section as normal & you should find they grow into new plants.(use a sharp clean knife) You should get up to 3 out of one large tuber, FREE.