Intervention group: They will receive an educational app designed to improve sleep, and will receive self-help training in a six-week training package.

Patients will receive written weekly information on accurate and relevant information regarding insomnia symptoms, physiological controls of sleep, sleep hygiene practices, healthy sleep behaviors

This intervention lasts for six weeks. The intervention is App-based and mainly consists of the most potent CBT techniques as well Health action process approach. Weekly feedback is provided by health psychologists.

The Pittsburgh Sleep Quality Index includes seven components of subjective sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbances, the use of sleep medications and day time dysfunctions provide a total score of these seven components that allows us to better understand the quality and quantity of one's sleep. The Pittsburgh Sleep Quality Index is a self-reporting instrument consisting of nine questions designed to measure the quality of sleep disorders in a period of one month. The scale scores range from 0 to 21, with higher scores indicating poor quality of sleep and scores less than 5 considered as high quality of sleep

Sleep hygiene behaviour will use three items to measure how many days the participants had good sleep hygiene.

behaviour.

Zigmond and Snaith developed the 14-item HADS to measure the anxiety (7 items) and depression (7 items) of patients with both somatic and mental problems. The response descriptors of all items are Yes, definitely (score 3); Yes, sometimes (score 2); No, not much (score 1); No, not at all (score 0); except for items 7 and 10, which are scored reversely. A higher score represents higher levels of anxiety and depression: a domain score of 11 or greater indicates anxiety or depression; 8-10 indicates borderline case; 7 or lower indicates no signs of anxiety or depression. The two-factor framework of the HADS has been supported in cancer patients.