ZBrushCentral

After Sculpting I can not paint. New on the Forum.

Hi everyone, I’m just new on the forum with lot of questions behind. I hope to find the answers here with your support. I downloaded Sculptris amazing software a couple of days ago with the intention of purchasing later ZBrush, so after trying my first sketch I tried to paint it and here comes the problem. I can not, as it looks to slow down a lot the performance. The number of triangles looks quite high, 4940000, and I guess i have to reduce details, but I can not get with it. A pity now that I can not continue digging into it.
I would appreciate any recommendation about it.
Thanks in advance.
Carlos.