It's been many years since I've installed any sort of linux distro. Back in the day, yes, I would say all of the steps in this article would be required to successfuly dual boot Windows & Ubuntu.
But Ubuntu is on 16.10 now. Should I just try the "Install Ubuntu alongside windows" option and let Ubuntu sort of figure out partitions/boot manager/everything? Or will I end up with a broken boot manager or messed up partition?
I've only skimmed the page to which you linked, but it looks basically reasonable, with one caveat: The page gives insufficient detail on how to determine your boot mode and control the boot of the Ubuntu installation medium to the correct mode. In brief, most computers with Windows 8 and later come with Windows installed in EFI/UEFI mode. Most (but not all) Windows 7 installations use BIOS/CSM/legacy mode, as do the vast majority of earlier Windows versions. If you installed Windows yourself, all bets are off, except for older versions (Vista and earlier, except on exotic platforms), which support only BIOS mode.
It's imperative that your Ubuntu installation use the same boot mode as your Windows installation. See this page of mine for information on determining your current boot mode. See this other page of mine for information on the Compatibility Support Module (CSM) and how to control the boot mode of your Ubuntu installation medium.
If you install Ubuntu in the wrong boot mode, you'll find it difficult or impossible to control which OS boots; hence the importance of getting this detail right.
One more caveat: Some (too many) computers have broken EFIs that forget their boot settings. If you're unlucky enough to have such a computer, you'll have to employ ugly workarounds to fix the problem. Numerous questions and answers on this site address such problems. See this one as a starting point.
Dual boot is pre-virtualization and unnecessary unless you need direct access to your hardware, in which case I would boot from an external medium anyway. Especially for something trivial like trying another OS, virtualization is a better solution. Look for virtualbox or vmware player.
