Schematics... schematics... how, what file format, what software...? Have I mentioned that I am a bloody layman? - Another few hours online in the electronics design jungle.
I ended up with EasyEDA. So far I'm quite fine with it.
I finally cobbled something together which almost looks like a schematic, but it's very... unoptimized... :-)
I'm going to optimize it and clean it up a bit first, it's too embarrassing for publishing now, but confident it is basically working, though. Will be back asap, but I'm not too fast, as it is a pure hobby project happening besides life, work, cooking, pets and such.