The common Sqitch guides are:

  changes             Specifying changes for Sqitch
  configuration       Hierarchical engine and target configuration
  environment         Environment variables
  passwords           Specifying target passwords
  tutorial            PostgreSQL Tutorial
  tutorial-firebird   Firebird Tutorial
  tutorial-mysql      MySQL Tutorial
  tutorial-oracle     Oracle Tutorial
  tutorial-sqlite     SQLite Tutorial
  tutorial-vertica    Vertica Tutorial

See sqitch help <command> or sqitch help <concept> to read about a specific command or concept.