A level 2 schedule is the second level of the WBS, and is more detailed than the level 1 schedule. Every item in a level 2 schedule is actually a sub-category of a level 1 schedule.
Let's say, for example, a level 1 schedule has:
Let's look of the level 2 schedule under "Design"
We can have:
1.1 Conceptual Design
1.2 Photoshop Design
1.3 Cutting the PSD into HTML mockups