# Build groups

In most cases, you build a single documentation instance, but sometimes you need to build several instances as one documentation website. This is when you need to configure a build group that defines the instances to be built.

Procedure: Define build group

1. Create a file named `build-groups.xml` in the  [cfg directory](help-modules.html#build-config-dir) .

You can right-click the `cfg` directory, then select `New | build-groups.xml`.

2. Define one or several build groups, specifying the instance IDs that should be built together in each group.

```XML
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE build-groups SYSTEM "https://resources.jetbrains.com/writerside/1.0/build-groups.dtd">
<build-groups
        xsi:noNamespaceSchemaLocation="https://resources.jetbrains.com/writerside/1.0/build-groups.xsd"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <build-group name="all-user-docs">
        <instance instance-id="ug" alias="User Guide" path="/userguide"/>
        <instance instance-id="cr" alias="Client Reference" path="/clientref"/>
    </build-group>

</build-groups>
```

You can select this build group in the [local build configuration](local-build.html), when [building with docker](build-with-docker.html), or when automating the build and publication via [GitHub](deploy-docs-to-github-pages.html), [GitLab](deploy-docs-to-gitlab-pages.html), or [TeamCity](build-on-teamcity.html).

When you build a group of instances, Writerside produces a ZIP archive with a separate directory for each instance and the `index.html` file in the root. The index file redirects from the root to the home page of the first documentation instance in the group.

If we consider the example `build-groups.xml` above, the `all-user-docs` group will produce an archive with the following:

* Two directories: `userguide` with the `ug` instance website and `clientref` with the `cr` instance website.

* `index.html` file in the root directory that redirects to the home page of the `ug` instance.

* In each help instance, there will be a switcher with two items: `User Guide` to open the `ug` help instance website and `Client Reference` to open the `cr` help instance website.