[DOCS] Add info about configuring ML (elastic/x-pack-elasticsearch#1497)

Original commit: elastic/x-pack-elasticsearch@a9dfc239cc

docs/en/ml/configuring.asciidoc

@@ -0,0 +1,33 @@
+[[ml-configuring]]
+== Configuring Machine Learning
+
+If you want to use {xpackml} features, there must be at least one {ml} node in
+your cluster and all master-eligible nodes must have {ml} enabled. By default,
+when you install {xpack}, all nodes are {ml} nodes. For more information about
+these settings, see <<ml-settings>>.
+
+To use the {xpackml} features to analyze your data, you must create a job and
+send your data to that job.
+
+* If your data is stored in {es}:
+
+** You can create a {dfeed}, which retrieves data from {es} for analysis.
+** You can use {kib} to expedite the creation of jobs and {dfeeds}.
+
+* If your data is not stored in {es}, you can <<ml-post-data,POST data>> from any
+source directly to an API.
+
+The results of {ml} analysis are stored in {es} and you can use {kib} to help
+you visualize and explore the results.
+
+For a tutorial that walks you through these configuration steps,
+see <<ml-getting-started>>.
+
+//Though it is quite simple to analyze your data and provide quick {ml} results,
+//gaining deep insights might require some additional planning and configuration.
+//The scenarios in this section describe some best practices for generating useful
+//{ml} results and insights from your data.
+
+//* <<ml-configuring-aggregation>>
+
+//include::aggregations.asciidoc[]

docs/en/ml/index.asciidoc

@@ -29,6 +29,7 @@ from {es} for analysis and anomaly results are displayed in {kib} dashboards.
 
 include::overview.asciidoc[]
 include::getting-started.asciidoc[]
+include::configuring.asciidoc[]
 // include::ml-scenarios.asciidoc[]
 include::api-quickref.asciidoc[]
 //include::troubleshooting.asciidoc[]  Referenced from x-pack/docs/public/xpack-troubleshooting.asciidoc