Mind have put together useful guides to explain the Mental Health Act 1983, Sectioning and Independent Mental Health Advocacy. Please follow the links below for more information:
Mental Health Act 1983:
What is the Mental Health Act 1983, what does it cover and what are my rights? - What is the Mental Health Act 1983? - Mind.
Sectioning:
What is sectioning? - Sectioning - an overview - Mind
Advocacy Service:
What is an Independent Mental Health Advocacy Service? - IMHAs in England - Mind