The walk-through guide
When you first run L3DT1) you will be prompted whether you wish to read the 'walk-through guide':
The walk-through is a sequence of simple pop-up descriptions that explain what you're seeing in L3DT and what to do next. Ideally, using the walk-through should be obvious and intuitive, as on the first page it explains how to use the guide:
Re-activating the walk-through guide
To re-activate the walk-through guide, click on the 'Help→Walk-through' menu option.
1)
As of L3DT release 2.4 and after.