When things are "scattered", it means that they are located randomly around a location. They're not straight, grouped together, or in order. Imagine a stack of cards which have been dropped on the floor:
The cards were scattered all over the floor.
When things are "scattered" in several different locations, you can use the phrase "scattered across ___". For example:
These days, my family is scattered across a dozen different countries around the world.
Different pieces of information are scattered across different departments, and it's hard to figure out who knows what.