Kinda can't make a video or site atm, but here's a few basics for ust writing in classic utau:
☆Start Stuff☆
--> always set ur tempo (BPM) first and foremost
☆Changing note length☆
--> right-click on a note > click length > adjust the number
--> common note length values:
Quarter note = 480
Eighth note = 240
Sixteenth note = 120
☆Changing octaves☆
--> Select all notes > click edit > move region by number > type in 12 (octave up) or -12 (octave down)
--> You can just set a number between 1-11 if you want the ust in a different key
☆Changing the note lyrics☆
--> you can double-click a note and type in the lyric
--> if you made the melody before adding the lyrics, then you can type the lyrics into the "lyric box" > select all notes > click the "substitute lyrics" or "insert lyrics" button
--> let's say you want to split the ust for separate vocalists; type a whole bunch of "R"s into the lyric box > select the regions that the vocalist won't sing > substitute lyrics
☆Tuning Tips☆
--> a pitchbend plugin will do you far better than whatever classic utau has
--> use pitchbends to raise/lower a held note rather than placing another vowel (it's often keeps the vocals sounding smoother)
--> if the held note is required to be tuned a certain way, then it might be better to place another vowel in that case (it gives more pitchbend flexibility)
Im still not really sure what ur asking for, but if it helps, i heard that openutau has a function/plugin that can extract the notes from a song and make a rough midi.