The Quick Start is a really good place to start – it will show you briefly how to use the index classes and describes them at a high level.
The downloadable source for each release contains several samples for you to investigate. You can also download the API documentation generated from the source code.
Constructing full text indexes
Find out how to construct the various full text index classes, FullTextIndex, UpdatableFullTextIndex and PersistedFullTextIndex.
Understand the various ways that word splitters can be used to process text being indexed and searched.
Searching the full text index
Learn the LIFTI query syntax used to parse queries with the LiftiQueryParser.
Persistence File Format