For questions about the handling of tense, aspect, and mood in constructed languages.
Tense, Aspect, and Mood are often interwoven in natural languages and regarded as one system in linguistics.
Tense is used to express when an event happens. Examples of tenses are present, past, and future.
Aspect is used to describe the internal structure of an event -- for example, whether an action is ongoing or completed, whether it happens over and over or only once, and many other such distinctions. There are a great number of different aspects observed in natural languages. Many languages combine tense and aspect, but many others treat them separately or only overtly mark one or the other.
Mood is used to express modality -- a speaker's beliefs about how true, obligatory, or desirable something is. This can include many things: belief that an event occured (or will occur) in reality, desire for an event to occur, uncertainty about whether something has occured, ordering someone to bring a particular event about, and much more.
The system of tense-aspect-mood (sometimes abbreviated TAM) is sometimes extended to include polarity (negation and related phenomena) and/or evidentiality (what evidence the speaker has that what they said is the case).