Start with SNAP CIRCUITS toys. Even if your an adult, these are a start.
Then upgrade to a ELEGOO UNO Electronics kit off Amazon.
It'll give you the basics of powering stuff, and then basics of signals.
Some kind of RC Car, Multicopter, Self built 3D Printer hobby will also help get you started.
No matter what printer you get,
I recommend avoiding any printer designed to move the bed in the Y-Axis.
It's an old design prior to CoreXY and it isn't needed anymore, and has a lot of cons compared with no pros.