If different websites or guidebooks give you different instructions for visiting a shrine or temple, the safest choice is usually to follow the guidance at the place itself. If there is a sign explaining what to do, it makes more sense to follow that than to insist on a method you found online beforehand.
There are widely known customs for shrine and temple visits, but the details are not identical everywhere. Shrines and temples are different from each other, and individual places may also have their own practices. Trying to find one perfectly correct set of rules that applies everywhere can make things more confusing than they need to be.
If there are no special instructions, watching what people around you are doing is often enough. A foreign visitor who bows one time too many or gets the order at the purification basin slightly wrong is unlikely to cause a serious problem. Japanese visitors do not necessarily know every small detail at every shrine or temple either.
What matters much more is ignoring rules that the place clearly sets out. Walking into an area marked “Do Not Enter” or taking photos where photography is prohibited is very different from making a small mistake in ritual etiquette. A small mistake in etiquette is one thing. Ignoring a rule that is clearly posted is much more likely to cause concern.
Shrines and temples are not important only to people with strong religious beliefs. Many Japanese people who do not think of themselves as especially religious still tend to treat these places as something sacred, or at least as places that should not be treated carelessly. Because of that, a visitor’s attitude often matters more than perfect technique.
If an online guide says one thing but the shrine or temple says another, follow the local guidance. If there is no guidance, watch what people around you are doing and behave respectfully. You may not get every detail right, but showing respect for the place and consideration for others will usually matter far more than performing every step perfectly.