build: add Docker Build overview page

Signed-off-by: CrazyMax <[email protected]>

_data/toc.yaml

@@ -1400,6 +1400,8 @@ manuals:
 
 - sectiontitle: Docker Build
   section:
+  - path: /build/
+    title: Overview
   - sectiontitle: Buildx component
     section:
     - path: /build/buildx/

build/buildx/index.md

@@ -1,7 +1,7 @@
 ---
 title: Buildx component
 description: Working with Docker Buildx
-keywords: Docker, Buildx, BuildKit
+keywords: build, buildx, buildkit
 redirect_from:
 - /buildx/working-with-buildx/
 ---

build/buildx/install.md

@@ -1,7 +1,7 @@
 ---
 title: Install Docker Buildx
 description: How to install Docker Buildx
-keywords: Docker, Buildx, BuildKit
+keywords: build, buildx, buildkit
 ---
 
 ## Docker Desktop

build/index.md

@@ -0,0 +1,50 @@
+---
+title: Overview of Docker Build
+description: Introduction and overview of Docker Build
+keywords: build, buildx, buildkit
+---
+
+Docker Build is one of the most used features of the Docker Engine - users
+ranging from developers, build teams, and release teams all use Docker Build.
+It uses a [client-server architecture](../get-started/overview.md#docker-architecture)
+that includes several tools. The most common method is to use the Docker CLI with
+[`docker build` command](../engine/reference/commandline/build.md) that sends
+requests to the Docker Engine that will execute your build.
+
+Starting with version 18.09, Docker supports a new backend for executing your
+builds that is provided by the [BuildKit](https://github.com/moby/buildkit)
+project. The BuildKit backend provides many benefits compared to the old
+implementation. As there is a new backend, there is also a new client called [Docker Buildx](buildx/index.md),
+available as a CLI plugin that extends the docker command with the full
+support of the features provided by BuildKit.
+
+BuildKit is enabled by default for all users on [Docker Desktop](../desktop/index.md).
+If you have installed Docker Desktop, you don't have to manually enable BuildKit.
+If you have installed Docker as a [Linux package](../engine/install/index.md),
+you can enable BuildKit either by using an environment variable or by making
+BuildKit the default setting.
+
+To set the BuildKit environment variable when running the
+[`docker build` command](../engine/reference/commandline/build.md), run:
+
+```console
+$ DOCKER_BUILDKIT=1 docker build .
+```
+
+To enable BuildKit backend by default, set [daemon configuration](/engine/reference/commandline/dockerd/#daemon-configuration-file)
+in `/etc/docker/daemon.json` feature to `true` and restart the daemon. If the
+`daemon.json` file doesn't exist, create new file called `daemon.json` and then
+add the following to the file:
+
+```json
+{
+  "features": {
+    "buildkit": true
+  }
+}
+```
+
+If you're using the [`docker buildx build` command](../engine/reference/commandline/buildx_build.md),
+BuildKit will always being used regardless of the environment variable or backend
+configuration. See [Build with Buildx](buildx/index.md#build-with-buildx) guide
+for more details.