I am not a layer not patent attorney, but I have extensive experience as a former asset manager of a IP portfolio of an international stock market traded information company and inventor/co-inventor on multiple US and non-US patents and patent applications.
This sentence is poor advice, since the one-year rule exists only in the U.S., whereas other countries have stricter rules. So it is recommended to always keep things secret (meaning you can only tell people under NDA about it) until a patent application is filed. You will normally want to be able to exercise your patent rights (a government-granted, time-limited, territorial monopoly) in multiple jurisdictions, not just the U.S., as your competitors will likely sit not just in the U.S. (if you file only in one country, people can work around your patent by using the method disclosed therein in another, unprotected jurisdiction instead, which is perfectly legal).
Another piece of advice, namely to file a provisional application first, is only advisable if you are not quite ready to file the full application, yet you are afraid someone else may file first. In most circumstances it may be smarter to file a full application as the first action; the reason is that no new material matter may be added to the provisional application, and in the course of writing and "fine tuning" the language of the final application, one often wishes to include additional matter. To sum it up, a provisional freezes the scope of the application, while not providing you an earlier "priority date".
You need to understand IP well to play this game; most people don't. It's also a game with large capital requirements ($100k/lifetime of a patent, including extension fees, foreign filings and translations) and very long time lines (double decades rather than weeks). But if executed carefully, a single transaction (case of patent litigation or licensing) may bring an IP owner more $$$ than they may earn with their normal operational business.