Creating index - settings vs mapping


I want to create index and tell ElasticSearch to index specific fields from my document.

My document is Event (ID,NAME,DESCRIPTION,DATE) and i will put such documents into index.

I want to tell ElasticSearch, that when I search documents it should check NAME and DESCRIPTION fields. I quess I should point NAME an DESCRIPTION fields and their types and index stragegy, for example analyze.

I create index:

CreateIndexRequestBuilder createIndexRequestBuilder = client.admin().indices().prepareCreate(name).setSettings(???);


What is the difference between settings and mapping and where should I provide the index strategy for NAME and DESCRIPTION?

Also.. where to pass the type of the document that I want to index? For example indexName is provided in prepareCreate(indexName), where documentType should be provided?