When you install Bitwig, check your previous version/files, because if you made your projects on Bitwig 3 and then you install bitwig 2.4, it won't open your projects from 3.

Tracks greyed out, upper left of arranger (below 4/4 and bpm) there's a box with like 3 grey lines: click it

Switch to PulseAudio so you can have multiple things playing audio at a time (48000 worked for me for less crackliness)

VST plugins, where to put them.

Create multisamples in Bitwig

https://www.youtube.com/watch?v=2_9kbGYzSbQ

Create a new Sampler instanace and click ‘create new multisample’ on the unit.

Just drag the set of files, so long as they're convention-named like ‘V1 C2 TheSynth’