[Feature][Doc] Add Config file introduce.

docs/en/concept/config.md

@@ -0,0 +1,108 @@
+---
+sidebar_position: 2
+---
+
+# Intro to config file
+
+In SeaTunnel, the most important thing is the Config file, through which users can customize their own data
+synchronization requirements to maximize the potential of SeaTunnel. So next, I will introduce you how to
+configure the Config file.
+
+## Example
+
+Before you read on, you can find config file
+examples [here](https://github.com/apache/incubator-seatunnel/tree/dev/config) and in distribute package's
+config directory.
+
+## Config file structure
+
+The Config file will be similar to the one below.
+
+```hocon
+env {
+  execution.parallelism = 1
+}
+
+source {
+  FakeSource {
+    result_table_name = "fake"
+    field_name = "name,age"
+  }
+}
+
+transform {
+  sql {
+    sql = "select name,age from fake"
+  }
+}
+
+sink {
+  Clickhouse {
+    host = "clickhouse:8123"
+    database = "default"
+    table = "seatunnel_console"
+    fields = ["name"]
+    username = "default"
+    password = ""
+  }
+}
+```
+
+As you can see, the Config file contains several sections: env, source, transform, sink. Different modules
+have different functions. After you understand these modules, you will understand how SeaTunnel works.
+
+### env
+
+Used to add some engine optional parameters, no matter which engine (Spark or Flink), the corresponding
+optional parameters should be filled in here.
+
+<!-- TODO add supported env parameters -->
+
+### source
+
+source is used to define where SeaTunnel needs to fetch data, and use the fetched data for the next step.
+Multiple sources can be defined at the same time. The supported source at now
+check [Source of SeaTunnel](../connector/source). Each source has its own specific parameters to define how to
+fetch data, and SeaTunnel also extracts the parameters that each source will use, such as
+the `result_table_name` parameter, which is used to specify the name of the data generated by the current
+source, which is convenient for follow-up used by other modules.
+
+### transform
+
+When we have the data source, we may need to further process the data, so we have the transform module. Of
+course, this uses the word 'may', which means that we can also directly treat the transform as non-existent,
+directly from source to sink. Like below.
+
+```hocon
+transform {
+  // no thing on here
+}
+```
+
+Like source, transform has specific parameters that belong to each module. The supported source at now check.
+The supported transform at now check [Transform of SeaTunnel](../transform)
+
+### sink
+
+Our purpose with SeaTunnel is to synchronize data from one place to another, so it is critical to define how
+and where data is written. With the sink module provided by SeaTunnel, you can complete this operation quickly
+and efficiently. Sink and source are very similar, but the difference is reading and writing. So go check out
+our [supported sinks](../connector/sink).
+
+### Other
+
+You will find that when multiple sources and multiple sinks are defined, which data is read by each sink, and
+which is the data read by each transform? We use `result_table_name` and `source_table_name` two key
+configurations. Each source module will be configured with a `result_table_name` to indicate the name of the
+data source generated by the data source, and other transform and sink modules can use `source_table_name` to
+refer to the corresponding data source name, indicating that I want to read the data for processing. Then
+transform, as an intermediate processing module, can use both `result_table_name` and `source_table_name`
+configurations at the same time. But you will find that in the above example Config, not every module is
+configured with these two parameters, because in SeaTunnel, there is a default convention, if these two
+parameters are not configured, then the generated data from the last module of the previous node will be used.
+This is much more convenient when there is only one source.
+
+## What's More
+
+If you want to know the details of this format configuration, Please
+see [HOCON](https://github.com/lightbend/config/blob/main/HOCON.md).

docs/en/faq.md

@@ -1,11 +1,8 @@
 # FAQ
 
-why-i-should-install-computing-engine-like-spark-or-flink
-
 ## Why I should install computing engine like Spark or Flink
 
-<!-- We should add the reason -->
-TODO
+Now SeaTunnel uses computing engines such as spark and flink to complete resource scheduling and node communication, so we can focus on the ease of use of data synchronization and the development of high-performance components. But this is only temporary.
 
 ## I have a question, but I can not solve it by myself
 

docs/en/start/local.mdx

@@ -11,7 +11,7 @@ import TabItem from '@theme/TabItem';
 
 Before you getting start the local run, you need to make sure you already have installed the following software which SeaTunnel required:
 
-* [Java](https://www.java.com/en/download/) (only JDK 8 supported by now) installed and `JAVA_HOME` set.
+* [Java](https://www.java.com/en/download/) (Java 8 or 11, other versions greater than Java 8 can theoretically work as well) installed and `JAVA_HOME` set.
 * Download the engine, you can choose and download one of them from below as your favour, you could see more information about [why we need engine in SeaTunnel](../faq.md#why-i-should-install-computing-engine-like-spark-or-flink)
   * Spark: Please [download Spark](https://spark.apache.org/downloads.html) first(**required version >= 2** and version < 3.x). For more information you could
   see [Getting Started: standalone](https://spark.apache.org/docs/latest/spark-standalone.html#installing-spark-standalone-to-a-cluster)

docs/sidebars.js

@@ -68,14 +68,20 @@ const sidebars = {
       items: [
         'start/local',
         'start/docker',
-        'start/kubernetes',
+        'start/kubernetes'
+      ],
+    },
+    {
+      type: 'category',
+      label: 'Concept',
+      items: [
+        'concept/config',
       ],
     },
     {
       type: 'category',
       label: 'Connector',
       items: [
-        'connector/config-example',
         {
           type: 'category',
           label: 'Source',