How to move from solr to elastichsearch?

Dear anyone,
currently I am using solr in my system, but now I would like to exchange to elastic. I do not know how to change from this config in solr to elastic. Please help to give me some solution. thanks a lot.

I configured in db-data-config.xml to fetch data from mysql to index by define entities like this:

<;dataSource type="JdbcDataSource" driver="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost:3306/bookstore" user="root" password="" />
<;entity name="book" query="SELECT id, title, author, category, description from book">
<;field column="id" name="id" />
<;field column="title" name="title" />
<;field column="description" name="description" />
<;entity name="category_name" query="SELECT cat_name FROM category c where = '${book.category}'">
<;field name="category_name" column="cat_name" />
<;entity name="author_name" query="SELECT name FROM author a where = '${}'">
<;field name="author_name" column="name" />
<;field column="last_modified" name="last_modified"/>

in both of entity : [catefory_name] and [author_name], the sql statement will get parameter
${book.category} and ${}'. It means that these both entities are transferring value from book as parameter to both entities(category_name and author_name).

the same way, I would like to make index and filter in elastic.
I am used jdbc to connect to mysql to make indices.
but I cannot make indices between parent and child relations at elastic.
what should I do in elastic?

thanks a lot.

best regards,