Energy
Common Energy (CE) is LTX Industries' way of referring to the energy API used by NeoForge. You might know it as Forge Energy, FE, Redstone Flux, RF, etc.
This tone of light blue is used as a context clue anywhere energy is used, referenced, upgraded, etc.
Before you dive into the tech tree, you're going to need to make energy. Ideally, you'll also want to make some energy storage. You can get by with just the built-in machine energy buffers early on, but these will become insufficient pretty quickly.