Setting and participants
ADHD
The focus group interviews were conducted online by using Tencent Meeting software, which is commonly used in business, municipal services, finance, education, healthcare, and other industrial fields and is widely used online and for interviews, learning, and training [Participants were parents with children with ADHD. They were recruited from the pilot RCT and by using purposive sampling. By applying homogeneous purposive sampling, the participants for the first two interview sessions were invited from the participants in the intervention group who were willing to attend the interview for a comprehensive understanding. For the third interview session, purposeful random sampling was used to minimize the potential bias due to pure criterion sampling [