English voicebanks are very complex and can be quite a big task for a beginner. A Japanese CV voicebank can help you work out the basic technical process, even if you have no plans to release the voicebank or use it for any songs. Once you have things working properly without issues or errors, it'll be easier to work on a bigger voicebank without running into problems.
Here's a CV Japanese recording list and the base configuration.
wastelandutau.neocities.org
Setup
Create a folder for your voicebank.
Inside that folder create a plain text file named "character.txt" and write this in the file.
INI:
name=(your utau's name here)
Create another plain text file named "oto.ini". Make sure you haven't accidentally named it "oto.ini.txt".
From the website, copy the box for "Romaji Base OTO" and paste it into your oto.ini file.
Recording
You'll need to use some recording software that can export WAV files, such as Audacity. Make sure you're recording in mono (1 track) not stereo (2 tracks). By default it should already be at 44100 Hz sample rate.
Right before you start a recording session, I recommend doing vocal warmups.
For a CV Japanese voicebank, each recording is 1 syllable only. Make sure you have a little bit of silence at the start and end of each recording. Sing the syllable for 1-2 seconds, and export each recording as its own 16bit wav file. Follow the recording list for what you need to record and how to name the files.
Configuration
This is an old guide that you could refer to, but I do need to rewrite it. Since you already have the base configuration you just need to adjust them to fit your recordings.
This guide was originally written in 2014 and rewritten in 2015, as a resource for newbies who received otoing services from this thread. http://utaforum.net/threads/services-for-newbies.8918/ I am now making this publicly available to the...
utaforum.net
Please keep in mind that, by default, OpenUtau will only read the aliases from your OTO and it will completely ignore the filenames. The provided base OTO will alias everything to hiragana, so you'll need to input hiragana lyrics in your project.