OK. Sampler is here, found a bunch of cool samples to import and mess around with. How do I tell Octamed to play a specific sample on the sampler? I have Midi Cable going from Midi out on my Triple Play to Midi In on the Sampler. Is this correct?
That is correct. What you do next, depends on your sampler. Assign a sample to a MIDI channel (no idea how your hardware works but it should be straightforward enough).
In OctaMED, check that MIDI is enabled (see menu). Open the instrument properties window (from the main panel) and choose the same MIDI channel for your instrument (slider at the bottom left of the properties window). Leave the preset number as zero for now, as changing it will send a MIDI present change message on that channel, your sampler might interpret that as a "switch sample" message or something.
Next, crank up the volume in the instrument properties and try a few notes. If you don't hear anything from your sampler, try raising your instrument transpose to 12 or 24 or even 36. OctaMED's MIDI note range doesn't match up to well with it's sample replay note range (except in mix mode), usually the MIDI notes are 2-3 octaves lower than you'd expect using the default transpose.