For a comprehensive documentation of MongoDB, refer to the MongoDB Manual. The following sections in the manual provide some starting points for developing with MongoDB.
Indexes and indexing strategies.
If the workload on the Atlas cluster is such that it impedes operations, including the ability to scale, MongoDB Atlas may, in some situations, create indexes in your cluster as a safeguard.
Data model design and examples with MongoDB.
Introduction to replica sets.
List of available MongoDB drivers.