∫∫∫ xy dV, where the solid is a tetrahedron with vertices (0,0,0), (1,0,0),(0,2,0), and (0,0,3)

I tried this with 0<x<1, 0<y<-2x+2, and 0<z<3 with no luck =\ Are my bounds wrong in this case?

What would be really helpful is if someone could explain how I am supposed to figure out the bounds. I don't even know how to figure them out which means I can't do any of the problems assigned