What the guidelines actually recommend
Two guidelines, and neither is quoted with a number, because none was read off the papers for this course.
What the research says
Edinger JD, Arnedt JT, Bertisch SM, Carney CE, and others (2021). Behavioral and psychological treatments for chronic insomnia disorder in adults: an American Academy of Sleep Medicine clinical practice guideline. Journal of Clinical Sleep Medicine, 17(2), 255 to 262 doi
Recommends the multi part behavioural treatment for long standing insomnia in adults, and recommends against sleep hygiene used on its own as a single component therapy. That second half is the reason this course does not consist of a list of tips.
Riemann D, Espie CA, Altena E, Arnardottir ES, and others (2023). The European Insomnia Guideline: an update on the diagnosis and treatment of insomnia 2023. Journal of Sleep Research, 32(6) doi
Places the same behavioural treatment as the first thing to try for long standing insomnia in adults, ahead of medication. Worth knowing before an appointment, because it means asking for a talking treatment for sleep is a reasonable request and not an unusual one.