Click track

museumman56 it all depends on how you want to run playback.
Option 1
Stereo track , main mono track on the left output and click track on the right output.
This is simple and easy to achieve and use, plug it in to two channels of your mixer, send left channel to PA both sides, send right click track channel to auxilary feeding your in ears, drummer monitors, or perhaps your monitor so you can hear the count in on your foldback but the audience only gets the music only, there are many uses that can be created with this simple method.
Using multitrack method you will need a lot more time in prep work and you need a lot more knowledge of computer and audio engineering and will benefit greatly if you need flexability in the way you operate a band, but if you are a solo artist the benefits are greatly reduced and in my opinion not worth the effort.

Option 2
Multitrack, you have six stereo tracks.
Use the first stereo track as your backing track and attach a click track on to any of the other five tracks. Output your stereo backing track to main output and the click track to auxiliary out.
You still have another 4 stereo tracks to use for whatever you need.You could simlify it by paning the first track to left and the click track to right and feed both outs to main out, this creates the same result and gives you some extra control of audio in ST3 like EQ and volume levels and on the run mute etc , but is it worth it, you have to import more separate files and stuff around more to achieve not much more.

I always used option 1 as it’s simple and easy and running mono through a pa sounds better in my opinion, stereo is not all that great in large venues where the audience is all over the place as they need to be in the centre point to benefit.
In live venues only a few people are in the ideal position all the rest of your audience will miss out on certain information of a stereo image because they are not standing in the right spot.
So to all my solo artists out there , try running in mono you will be sounding much better to the majority in the crowd.The stereo wank is ok used very sparingly live in big venues, and it’s really good if you are sitting in a lounge listening to music positioned perfectly.

TIP!
I have noticed some people using stereo with click track on left and music on right, this is not the best way to do it.
Reason , with mixers the right channel is joined to the left channel so you can feed the system with a mono sorce and get this signal on both channels, when you plug in to the right chanel this breaks that joint connection and assumes you are runing in stereo.
So left channel is first priority right channel is second.
For that reason you should have your left channel as main program and click track on right.
I am assuming that you are firstly concearned with what the audiance hears and secondly what you hear.