The purpose of auto-propagation is to leverage repetitive segments and re-use content. Configure and enable your auto-propagation preferences under Preferences > General Preferences > Auto-Propagation.
To leverage repetitive content:
Select a segment for translation in the TXLF Editor. In this example, a filtered search locates and identifies duplicate segments.
Enter the translation for the first target segment.
To commit terms, click Commit, then click Next Segment or press Alt+Down.
Once you commit the target segment, this updates the TM and automatically propagates the update to all identical target segments throughout the file.