Always the best place to start with a synth is the manual, especially the part of it that pertains to how it plays with other, ie MIDI!
Setting-up a bunch of synths to synchronise via MIDI is
usually a straightforward task. First thing is to do is to ascertain which channel each of your instruments are on so you can set up your sequencers and controllers to match them. To do this on the KSP, enter the utility menu (shift-project), select the MIDI Channel page, go down to track outputs and set the tracks to match your instruments' channels. Remember that you can't use track 1 and the Drum track at the same time, so perhaps start with track 2 as your channel 1 track.
The TD-3 seems to be hardwired to CH1, a little annoying but not a real issue.
The DrumBrute will be most likely on Ch10 by default (the standard MIDI drum channel), but best to just make sure. I'd hazard a guess that MCC will be able to tell you for sure, but just check your manual too be certain. Double check your manual also for how to ensure the DrumBrute is set to run on an external MIDI clock.
Your Volca Sample is really going to throw a spanner in the works though. It is an anomaly in that it runs on all 16 MIDI channels and doesn't have any hint of that in it's 'manual' (I use that term loosely).
Best thing to do there for the time being is to use its internal sequencer with your KSP as master the master clock. By default the Sample should play, stop and sync to MIDI clock, so you
should be able to just plug and play there. Start doing some reading on how to address it as an instrument in your MIDI collective. Head over to the
Korg Forum and start browsing through their threads regarding the
Volca Sample.
If it all becomes a bit too much, at least you can revert to using a 1/8 inch cable to run from the clock out on the KSP to the sync in on the Volca Sample. Volca's use 2ppq, so go into the KSP utility menu again, scroll down to the Sync page and choose 2PPQ for the output setting. You can change your Volca to run on 1PPQ too, but I'll skip on explaining that (it's in a chart on the massive sheet of paper they give you with the Volca and involves pressing Func while powering up).
Remember in the end the best way to have total control over your instruments is to read as much as you can about them. Not only have the manuals somewhere easy to get at, but also any other supplementary material too, such as the MIDI Implementation charts.