If you stick to one version, the API won’t change out from under you 
And the core parts (CRUD) of the LiteCore API don’t tend to change much.
Most of the docs are in Doxygen comments in the headers (c4Base.h, c4Database.h, etc.) The LiteCore wiki has some other docs on thread safety, the query syntax, etc. You’ll also need to look at the header docs in the Fleece submodule (FLSlice,h, Fleece,h) to understand how to access and create document properties.
For sample code, you can look at the “cblite” command line tool, which is at https://github.com/couchbaselabs/cblite [IIRC; typing from memory]. It has sub commands to do a lot of common db operations.