The document provides an overview of expressing state-of-being in Japanese using the particle "da". It explains that da is used to declare what something is by attaching it to a noun or na-adjective. It gives examples like "hito da" meaning "is a person". The document notes that desu is the polite form of da. It also explains that state-of-being can be implied without da and provides the example greeting "Genki?" "Genki." to ask and reply how someone is doing well. Finally, it states that da makes a statement more emphatic and is more commonly used by men, and will be needed in certain grammatical structures.