Easy-PC uses three sets of libraries, for the Schematic, for the PCB and for both to tie them together (Components).
A Component is used by both the Schematic editor and the PCB layout editor to tie the two applications together. Typically, a Component could be the Part name, such as 74LS00. This would use four NAND2 logic gates in the Schematic and a DIP14 footprint in the PCB, these would be referenced in the Component.
You can create Schematic-only Components, these will just have a Schematic symbol and Component definition, with no PCB footprint. You might use these for power and ground symbols for example.
Likewise, you can create a PCB-only Component, this would have just the PCB footprint and Component definition, with no Schematic symbol. You might use these for testpoints for example.