This is my first attempt at using the forum.
Welcome, then, Jack. I couldn't find much information on the Technics model that you listed; I found some similar models at [
this link found here] I'm basing my answer on the
PX-664 model [found here]. On the back of the keyboard, you should find a pair of 5-pin DIN jacks, labeled MIDI In & MIDI Out. I don't know what model of SoundBlaster that you have, but I'll guess that this has a pair of mini-DIN jacks on it, labeled in the same way. There should be some cables that came with it: they convert the mini-DIN to a standard size. You're also going to need a couple of standard MIDI cables; you can get those anywhere for cheap.
So, when you have everything that you need: connect MIDI In to MIDI Out. That's a MIDI cable from the MIDI Out of your Technics (through the mini-DIN convertor) to the MIDI In of your SoundBlaster. Take another cable, and connect from the converted MIDI Out of the SB back to the MIDI In of your KB. There's the physical connections. Later on, you might want to hook up the Technics' Line Out(s) to the Line In(s) of the SoundBlaster, so that you can record the audio output. It should be a pair of standard 1/4" jacks, or maybe RCA plugs.
OK, now you're going to need a software program to control the setup, and record and playback the stuff from your piano. That Pentium 3 is a little long-in-the-tooth, but you shouldn't have a problem with MIDI. Audio recording? Well, I'm not so sure. The trick is going to be to find something that still supports whatever operating system is in the computer (Win 98?). With any luck, there's something in there already that came with the SoundBlaster card.
When you've settled on a software program, there should be some kind of Options or Preferences menu, where you can get the program to recognize the MIDI hookup that you just did. It should say something like "Creative MIDI In/Out" or similar. Once this is configured, you should have the ability to record the note events from your piano into the computer, and playback those recorded notes on the KB (set Local Off on the Technics for playback).
There are tons of little nuances that might trip you up along the way, Jack, but these are the basic steps. If you get stuck, feel free to reply back, and we'll see if we can get them ironed out. HTH