Usage, tutorials and training

• usage/index.md: Introduction
• usage/reference.md: Contains individual function, method, and API documentation (built from package docs? Or link to built package website?)
• usage/getting-started/user.md
• usage/getting-started/admin.md
• usage/installing/* (whole folder for instructions on installing indifferent environments?)
• learn/courses/*
  • in-person as well as online material?
• learn/tutorials/*
  • in-person as well as online material?