[documentation] source overview

docs/docs/core/flow_methods.mdx

@@ -210,7 +210,7 @@ A data source may enable one or multiple *change capture mechanisms*:
 *   Configured with a [refresh interval](flow_def#refresh-interval), which is generally applicable to all data sources.
 
 *   Specific data sources also provide their specific change capture mechanisms.
-    For example, [`Postgres` source](../ops/sources/#postgres) listens to PostgreSQL's change notifications, [`AmazonS3` source](../ops/sources/#amazons3) watches S3 bucket's change events, and [`GoogleDrive` source](../ops/sources#googledrive) allows polling recent modified files.
+    For example, [`Postgres` source](../sources/#postgres) listens to PostgreSQL's change notifications, [`AmazonS3` source](../sources/#amazons3) watches S3 bucket's change events, and [`GoogleDrive` source](../sources#googledrive) allows polling recent modified files.
     See documentations for specific data sources.
 
 Change capture mechanisms enable CocoIndex to continuously capture changes from the source data and update the target data accordingly, under live update mode.

docs/docs/sources/index.md

@@ -6,6 +6,23 @@ description: CocoIndex Built-in Sources
 
 # CocoIndex Built-in Sources
 
+In CocoIndex, a source is the data origin you import from (e.g., files, databases, APIs) that feeds into an indexing flow for transformation and retrieval.
+
+| Source Type    | Description                        |
+|----------------|------------------------------------|
+| [LocalFile](/docs/sources#localfile)     | Local file system                        |
+| [AmazonS3](/docs/sources#amazons3)       | Object store (Amazon S3 bucket)          |
+| [AzureBlob](/docs/sources#azureblob)     | Object store (Azure Blob Storage)        |
+| [GoogleDrive](/docs/sources#googledrive) | Cloud file system (Google Drive)         |
+| [Postgres](/docs/sources#postgres)       | Relational database (Postgres)           |
+
+Related:
+- [Life cycle of a indexing flow](/docs/core/basics#life-cycle-of-an-indexing-flow) 
+- [Live Update Tutorial](/docs/tutorials/live_updates) 
+for change capture mechanisms.
+
+
+
 ## LocalFile
 
 The `LocalFile` source imports files from a local file system.
@@ -262,7 +279,7 @@ The spec takes the following fields:
     :::info
 
     Since it only retrieves metadata for recent modified files (up to the previous poll) during polling,
-    it's typically cheaper than a full refresh by setting the [refresh interval](../core/flow_def#refresh-interval) especially when the folder contains a large number of files.
+    it's typically cheaper than a full refresh by setting the [refresh interval](/docs/core/flow_def#refresh-interval) especially when the folder contains a large number of files.
     So you can usually set it with a smaller value compared to the `refresh_interval`.
 
     On the other hand, this only detects changes for files that still exist.

docs/docs/targets/index.md

@@ -12,14 +12,16 @@ The way to map data from a data collector to a target depends on data model of t
 
 ## Targets Overview
 
-| Target Type    | See Also                    |
+| Target Type    | Description                   |
 |------------------|-------------------------|
 | [Postgres](/docs/targets/postgres) | Relational Database, Vector Search (PGVector)   |
 | [Qdrant](/docs/targets/qdrant)     | Vector Database, Keyword Search       |
 | [LanceDB](/docs/targets/lancedb)   | Vector Database, Keyword Search         |
 | [Neo4j](/docs/targets/neo4j)       | [Property graph](#property-graph-targets)        |
 | [Kuzu](/docs/targets/kuzu)         | [Property graph](#property-graph-targets)        |
 
+If you are looking for targets beyond here, you can always use [custom targets](/docs/custom_ops/custom_targets) as building blocks.
+
 
 ## Property Graph Targets
 Property graph is a widely-adopted model for knowledge graphs, where both nodes and relationships can have properties.