No trouble at all — that’s exactly why this forum is here!
Not knowing the details of what you were going for, I’m glad I could manage to offer something in the form of the online manual link.
Regarding playback sounds, Dorico assigns instrumental sounds to players based on the combination of what libraries you have installed and Playback Templates, found in the Play menu.
(N.B. The Play menu is not the same thing as Play Mode, the tab you click to see the Key Editor etc.)
What version/level of Dorico are you running (SE, Elements, Pro) and what instrument library/-ies do you have installed? (Since you’re using the Aria player, I’m guessing GPO5 is one…?)
For a great instrumental library, I can recommend highly NotePerformer. It’s a brilliant third-party library that “plays very nicely” with/in Dorico right out of the virtual box. Generally abbreviated here in the forum as NP, you’ll see it pop up all over the place in discussions. The (IMO meager) cost of $129 — which I believe is a lifetime license (!) — has to be among the best 129 smackolas I’ve ever spent.
Finally, for future reference you’ll find that the best way to let us know what you need help with might include a screen grab if it’s a simple enough kind of question, and/or an actual Dorico project file.
You’ll be able to upload them once the new-forum-member limitations (totally understandable from Discourse’s perspective, but kind of ironic in this case, since our newest Dorico users are among those likely to need help). Daniel wrote great instructions in section 4 of this post: