fixed 352a9e5e from https://gitee.com/esterzhou/docs/pulls/15954

Add doc (14219)
Signed-off-by: Nester.zhou <ester.zhou@huawei.com>

en/application-dev/quick-start/full-sdk-compile-guide.md

+# Full SDK Compilation Guide
+
+The full SDK provides a full set of APIs available in OpenHarmony, including system APIs required by system applications. Vendors can leverage this SDK to develop applications.
+
+Since OpenHarmony 3.2 Beta5, the full SDK is not provided with the version. If necessary, you can compile the SDK using the full source code.
+
+## Compiling the Full SDK
+
+**Preparation**
+
+1. Register an SSH public key for access to Gitee.
+2. Configure the server environment. For details, see [Setting Up the Ubuntu Environment](../../device-dev/quick-start/quickstart-ide-env-ubuntu.md).
+
+**Procedure**
+
+1. Download and initialize the manifest repository: **repo init -u https://gitee.com/openharmony/manifest.git -b $manifest_branch --no-repo-verify --repo-url=https://gitee.com/oschina/repo --no-clone-bundle**
+
+2. Download source code based on the downloaded manifest repository: **repo sync -c -d --force-sync**
+
+3. Perform precompilation: **yes y | apt install libxinerama-dev libxcursor-dev libxrandr-dev libxi-dev && rm -rf prebuilts/clang/ohos/darwin-x86_64/clang-480513 && rm -rf prebuilts/clang/ohos/windows-x86_64/clang-480513 && rm -rf prebuilts/clang/ohos/linux-x86_64/clang-480513 && bash build/prebuilts_download.sh -ndk && apt-get update -qqy && apt-get install doxygen -y --force-yes**
+
+4. Perform compilation: **./build.sh --product-name ohos-sdk**
+
+
+If the compilation is successful, export the files in the **out/sdk/packages/ohos-sdk/** directory.
+
+## Replacing the SDK
+
+After the full SDK is compiled, switch to it in DevEco Studio. For details, see [Guide to Switching to Full SDK](../../application-dev/quick-start/full-sdk-switch-guide.md).