@GPTech2444have you created parts in Eagle before?
Either way -
Each component has 3 distinct elements:
SYMBOL - [MANDATORY] Used while making schematics to provide a graphical representation of electrical connections
FOOTPRINT - [MANDATORY] Used to define the physical shapes of the electrical contacts and, solder mask, solder paste, and text labels on the circuit board layout.
3D MODEL - [OPTIONAL] A 3D model is oriented and aligned with the FOOTPRINT which allows Fusion 360 to render a 3D circuit board.
All three of those elements are ultimately combined into a DEVICE which has all the information necessary for every step in the design process. The basic elements FOOTPRINT, SYMBOL, and 3D MODEL can be re-used in multiple DEVICES. For example, in a library with resistors you will have a single SYMBOL for a resistor that are used in a schematic, but you can marry any number of unique FOOTPRINTS to that SYMBOL to represent the myriad of different physical shapes of real resistors. Further, in a DEVICE, you can take a SYMBOL/FOOTPRINT combination and create variants for each value that you may use.
An introduction to library concepts in EAGLE. The concepts in Fusion are basically the same, but it looks different. Learning the concepts first, makes learning the UI easier.
More specific on importing parts in Eagle:
Hope this helps you and others.
Carlos Acosta
Factory400 - YouTube|Instagram