Those two arrangements in the diagram are functionally the same.
The best way would be to use a transformer. Simplest is to purchase a DI box from a guitar center (Radial JDI Stereo or JDI Duplex are pretty good, though pricey)
This is a better reference when you start fiddling with adapters:
http://www.rane.com/note110.htmlIf feeding RCA into XLR, then the rca tip goes to pin2 and the rca sleeve goes to pin3, connect pin1 to the cable shield but float it at the rca end.
If going from XLR to RCA... ugh just don't. Most of the time you'll luck out because both halves of the "balanced" outputs happen to be symmetrical around 0V (or the negative simply sits at 0V), but in the rare case that this isn't the case, floating pin3 is going to give you bad mojo.