I wrote up a reasonably detailed explanation of how everything in the percussion side of things fits together, which you can read here. It’s conceptually the same in Dorico as it is in Sibelius: you have a notehead of a particular appearance on a particular position on the staff, and this is mapped to a specific combination of percussion instrument and playing technique, and that is in turn mapped to a particular MIDI pitch on a particular patch.
Percussion is one of the more fiddly areas, but that’s not entirely Dorico’s fault: everybody wants to use their own notation (beyond drum set notation), every sample library provider provides different sets of sounds, and there is even confusion over which sound is on which note because different applications disagree over something as basic as the octave number for middle C.
I’m certainly willing to help you get this sorted out. Hopefully you have found over the course of your trial period that Dorico has lots of other things going for it, even if getting correct percussion playback is currently stumping you.