how to assign midi channels...newb question

Issue: I cannot get my DAW to play more than 1 instrument sound at a time when I have multiple MIDI tracks.
Gear/Versions: Presonus Studio One 2 Pro x64
Steinberg /software: Trial of HALion Symphonic Orchestra
PC/OS: Windows 10Pro x64 laptop
What I’ve done: I imported a MIDI file of a concert, with 14 tracks featuring most common orchestral instruments.
I’ve googled & looked through the manual, and I cannot find what I’m doing wrong…

Example Presonus channel setup looks like this:

What I don;t understand is how I tie a Presonus channel with a instrument in the VST interface…?

Sorry if this is horrendously noobish…
Help/direction is greatly appreciated!