I'd like to arrange a song that doesn't have or has little guitar onto fingerstyle guitar. Finding individual notes is tedious but simple, but how do you find chords, especially when it's not even the same instrument? I often see people, on YouTube for example, arrange something like this onto piano or guitar. I realize that arranging a song is a difficult process, but I find it hard to believe that it's simply a guessing game to find the chords, as trying to guess individual notes is already a long and tedious process.
One way I can think of to do this is to just guess what sounds right, and while there are some people who do actually do that, there are many that make pretty accurate versions of the song they're arranging.
My confusion comes with the part after you identify the first notes. Okay, I've got the first few notes. Now what? How do I put this into a form that's friendly to fingerstyle guitar? How do I even make a chord out of this? Do I just create chords from the root note until I find one that sounds good or right? If so, how do I determine how many notes should be in the chord? I feel like the difficultly is logarithmically increasing each time I ask a question!