[z2h-a6n]

In addition to the other recommendations in the thread, it may be useful to learn how the whole process works (KiCad, ordering or making PCBs, and assembling everything) with an even simpler circuit with just a few components. Making a simple battery + LED + resistor + switch circuit would involve learning almost the same amount about KiCad etc. as a more complicated circuit (within reason), with a lot less opportunity to be overwhelmed by component selection, PCB layout, etc. It would also be fairly cheap to make mistakes, since the PCB could be quite small and would probably cost only a few dollars even from a fairly high-end PCB manufacturer (I like OSH Park, but they can be expensive for large boards; see pcbshopper.com for price comparison).