See the glossary definition of Base Document.
  1. Click on the edition containing the collation
    • The edition will open in the editor
  2. Click on a comparison in the "Comparisons in this Edition" section
    • The comparison will open
  3. Click on Heatmap
    • The differences between the witnesses will be highlighted on the base document
  4. Click on Side-by-Side
    • Both witnesses will appear side-by-side; hovering over lines between the witnesses will highlight the differences between them one at a time