cloud: update the index page according to the latest TOC

TOC-tidb-cloud.md

@@ -16,6 +16,7 @@
   - [Try Out TiDB Cloud CLI](/tidb-cloud/get-started-with-cli.md)
   - [Perform a PoC](/tidb-cloud/tidb-cloud-poc.md)
 - Key Concepts
+  - [Overview](/tidb-cloud/key-concepts.md)
   - [Architecture](/tidb-cloud/architecture-concepts.md)
   - [Database Schema](/tidb-cloud/database-schema-concepts.md)
   - [Transactions](/tidb-cloud/transaction-concepts.md)
@@ -249,7 +250,7 @@
       - [Migrate Existing and Incremental Data Using Data Migration](/tidb-cloud/migrate-from-mysql-using-data-migration.md)
       - [Migrate Incremental Data Using Data Migration](/tidb-cloud/migrate-incremental-data-from-mysql-using-data-migration.md)
       - [Migrate and Merge MySQL Shards of Large Datasets](/tidb-cloud/migrate-sql-shards.md)
-      - [Migrate from On-Premises TiDB to TiDB Cloud](/tidb-cloud/migrate-from-op-tidb.md)
+      - [Migrate from TiDB Self-Managed to TiDB Cloud](/tidb-cloud/migrate-from-op-tidb.md)
       - [Migrate from MySQL-Compatible Databases Using AWS DMS](/tidb-cloud/migrate-from-mysql-using-aws-dms.md)
       - [Migrate from Amazon RDS for Oracle Using AWS DMS](/tidb-cloud/migrate-from-oracle-using-aws-dms.md)
   - Import Data into TiDB Cloud

tidb-cloud/_index.md

@@ -12,20 +12,22 @@ summary: TiDB Cloud is a fully-managed Database-as-a-Service (DBaaS) that brings
 
 [Why TiDB Cloud](https://docs.pingcap.com/tidbcloud/tidb-cloud-intro)
 
-[Architecture](https://docs.pingcap.com/tidbcloud/tidb-cloud-intro#architecture)
+[Key Concepts](https://docs.pingcap.com/tidbcloud/key-concepts)
 
 [FAQ](https://docs.pingcap.com/tidbcloud/tidb-cloud-faq)
 
 </LearningPath>
 
 <LearningPath label="Try" icon="cloud5">
 
-[Try Out TiDB Cloud](https://docs.pingcap.com/tidbcloud/tidb-cloud-quickstart)
+[Try Out TiDB Cloud Serverless](https://docs.pingcap.com/tidbcloud/tidb-cloud-quickstart)
 
 [Try Out TiDB + AI](https://docs.pingcap.com/tidbcloud/vector-search-get-started-using-python)
 
 [Try Out HTAP](https://docs.pingcap.com/tidbcloud/tidb-cloud-htap-quickstart)
 
+[Try Out TiDB Cloud CLI](https://docs.pingcap.com/tidbcloud/get-started-with-cli)
+
 [Proof of Concept](https://docs.pingcap.com/tidbcloud/tidb-cloud-poc)
 
 </LearningPath>
@@ -72,6 +74,8 @@ summary: TiDB Cloud is a fully-managed Database-as-a-Service (DBaaS) that brings
 
 [From Amazon S3 or GCS](https://docs.pingcap.com/tidbcloud/migrate-from-amazon-s3-or-gcs)
 
+[From TiDB Self-Managed](https://docs.pingcap.com/tidbcloud/migrate-from-op-tidb)
+
 [From CSV Files](https://docs.pingcap.com/tidbcloud/import-csv-files)
 
 [From Apache Parquet Files](https://docs.pingcap.com/tidbcloud/import-csv-files)
@@ -146,12 +150,12 @@ summary: TiDB Cloud is a fully-managed Database-as-a-Service (DBaaS) that brings
 
 <LearningPath label="Reference" icon="cloud-dev">
 
+[SQL Reference](https://docs.pingcap.com/tidbcloud/basic-sql-operations)
+
 [System Variables](https://docs.pingcap.com/tidbcloud/system-variables)
 
 [Release Notes](https://docs.pingcap.com/tidbcloud/tidb-cloud-release-notes)
 
-[SQL Reference](https://docs.pingcap.com/tidbcloud/basic-sql-operations)
-
 </LearningPath>
 
 </LearningPathContainer>

tidb-cloud/key-concepts.md

@@ -0,0 +1,59 @@
+---
+title: Overview of Key Concepts
+summary: Learn about the key concepts in TiDB Cloud.
+---
+
+# Overview of Key Concepts
+
+This document provides an overview of the key concepts in [TiDB Cloud](https://www.pingcap.com/tidb-cloud/). Understanding these concepts helps you better use TiDB Cloud features and capabilities.
+
+## Architecture
+
+TiDB Cloud is built on a cloud-native distributed architecture that separates computing from storage, enabling elastic scaling and high availability. [Learn more about TiDB Cloud architecture](/tidb-cloud/architecture-concepts.md).
+
+## Database schema
+
+TiDB Cloud enables you to organize and structure your data using objects such as databases, tables, columns, indexes, and constraints. It also supports advanced features such as temporary tables, vector indexes, and cached tables. [Learn more about database schema](/tidb-cloud/database-schema-concepts.md).
+
+## Transactions
+
+TiDB provides complete distributed transactions, and the model has some optimizations on the basis of [Google Percolator](https://research.google.com/pubs/pub36726.html). [Learn more about transactions](/tidb-cloud/transaction-concepts.md).
+
+## SQL
+
+TiDB is highly compatible with the MySQL protocol and the common features and syntax of MySQL 5.7 and MySQL 8.0. [Learn more about SQL in TiDB Cloud](/tidb-cloud/sql-concepts.md).
+
+## AI features
+
+The AI features in TiDB Cloud enable you to fully leverage advanced technologies for data exploration, search, and integration. [Learn more about AI features](/tidb-cloud/ai-feature-concepts.md).
+
+## Data Service (Beta)
+
+Data Service enables you to access TiDB Cloud data via an HTTPS request using a custom API endpoint. [Learn more about Data Service](/tidb-cloud/data-service-concepts.md).
+
+## Scalability
+
+TiDB Cloud Dedicated lets you adjust its compute and storage resources separately to match your data volume or workload changes. [Learn more about scalability](/tidb-cloud/scalability-concepts.md).
+
+## High availability
+
+TiDB Cloud ensures high availability in both TiDB Cloud Serverless and TiDB Cloud Dedicated clusters:
+
+- [High Availability in TiDB Cloud Serverless](/tidb-cloud/serverless-high-availability.md)
+- [High Availability in TiDB Cloud Dedicated](/tidb-cloud/high-availability-with-multi-az.md)
+
+## Monitoring
+
+TiDB Cloud provides comprehensive monitoring capabilities for cluster performance and health. [Learn more about monitoring](/tidb-cloud/monitoring-concepts.md).
+
+## Data streaming
+
+TiDB Cloud lets you stream data changes from your TiDB Cluster to other systems like Kafka, MySQL, and object storage. [Learn more about data streaming](/tidb-cloud/data-streaming-concepts.md).
+
+## Backup & Restore
+
+TiDB Cloud offers automated backup solutions and point-in-time recovery capabilities. [Learn more about backup and restore](/tidb-cloud/backup-and-restore-concepts.md).
+
+## Security
+
+TiDB Cloud provides a robust and flexible security framework designed to protect data, enforce access control, and meet modern compliance standards. [Learn more about security](/tidb-cloud/security-concepts.md).