Setup handles the first hours with new hardware: transferring data, joining a network, pairing accessories and correcting defaults that waste battery or leak information. Instructions run step by step and are tested on current software versions. For people who want a thing configured properly once, then forgotten.
Step-by-step walkthroughs for new devices: moving data across, fixing a weak network corner, and the default settings worth changing on day one.
A cable between your old and new Android phone moves apps, photos and settings in about 20 minutes — here's the exact order to do it in, and the three settings to finish before you use it.