OTHER GOOD SOURCES FOR OTO.INI HELP/TUTORIALS:
The oto.ini can be VERY confusing at first - especially if you're totally new to UTAU. The oto.ini is there to melt the notes together and add life to the UTAU, as well as some final editing for the .wavs.
There's lots of other great oto.ini tutorials out there, and I'll add links to those I found that I think could help after the tutorial :3
To open the UTAU oto.ini interface, do this:
This is the UTAU oto.ini interface - you have the first window and the second one, the second window opens when you push the large button placed near the four smaller ones (it's the big one to the left, see?). The second window is where we edit the oto.ini - the first window is for information on the oto, duplicating files and adding hiragana/romaji aliases.
As you can see, there's a lot of stuff going on here that I'll try to explain.
BLUE - the blue part indicates the part we want to delete from the file, for example if you recorded "zu" but forgot to erase the empty space in the beginning/end of the recording. That's where the blue goes. It's very handy owo
PINK - this part makes sure that your samples won't go "nnnnaaa" instead of "naaa", the pink goes over to consonant and partly over the vowel.
RED LINE - overlap, how much of the note/sound shall overlap the previous one.
GREEN LINE - This part is "preutter", IE. when the sound will actually start. For example, I want my UTAU to say "sama". I add the "sa" and "na", and the pre-utter turns it into "sa..ma" with a short pause for me. It's very convenient for realistic sounds!
NOTE!! NEVER drag the red and green lines TOO FAR or they'll sound OFF and BAD, experiment before releasing a voicebank with a newly configured oto.ini!!
STEP BY STEP
Oto'd Voicebank vs. No Oto Voicebank:
The first pic is of an oto.ini voicebank singing "arigato", the second of a voicebank with no oto.ini. See the differences? :3
The Oto.ini makes it go "a..riGaa..too", and the no oto goes "arigato". The first one sound a lot more realistic and nice.
Every voicebank should have a working oto before it's released.