It is rhizomatous and I believe tightly clustered leaves. Treat it like any other rhizomatous begonia and you should be fine - water properly, good light, go easy on fertilizer, good potting mix so it doesn't stay soggy wet. Keep any leaf litter cleared around the rhizomes as this can lead to rot and disease. If it is like Green Fountain, it will probably drop a lot of leaves late winter so don't be alarmed as it will soon put on new leaves and continue growing.

Thank You hc
Looking Forward To Growing This One...