Here is a short list of links to klystrack tutorials:

• klystrack for dummies and slow people (from 2015 but most of this still holds)
• klystrack wiki (the official "documentation", a bit out of date but also available in Japanese)
• the klystrack thread on ChipMusic.org (some nuggets of information here)

Don't forget there are a few example songs in examples/songs/n00bstar-examples.