You may need a general knowledge in device and device drivers in Linux (the BSDs behave the same but follows a simpler approach). Basically the naming scheme is based on the driver name with numbers and letters appended for device ordering. So sda1 means scsi disk (sd driver), a for the first one, and 1 for the first partition. Linux added a few folders and scheming for better interactivity.
/sys is powered by sysfs, which is actually a database as file and folders. OpenBSD doesn’t have it (and /proc too), so if you need to interact with kernel objects, you need to use C and the system library. But on Linux, you can do a lot with basic read and write on files.