Materials in EEVEE
Materials in EEVEE are not that different from materials in Cycles. Of course, there are many ways to get better materials in EEVEE that don't even exist in Cycles (and vice versa), but the main concept of materials is exactly the same as you are aware of with Cycles. The Blender developers have been really great at adding to the functionality of EEVEE so that materials that work with Cycles should mostly work with EEVEE (there are some exceptions, but for the most part this is true). If we look closely at the material output node in any material node tree, we can see that the default option is All, which means materials will work, regardless of whether you switch to Cycles or EEVEE in the render panel. We can focus our output by choosing a target engine. I find that to be extraneous, but it's good to know in case you want to hyper-focus your material development on one engine.
When creating art...