Copy overview.md and _index.md for the translation

Author: shuuji3

content/ja/docs/contribute/new-content/_index.md

@@ -0,0 +1,4 @@
+---
+title: Contributing new content
+weight: 20
+---

content/ja/docs/contribute/new-content/overview.md

@@ -0,0 +1,65 @@
+---
+title: Contributing new content overview
+linktitle: Overview
+content_type: concept
+main_menu: true
+weight: 5
+---
+
+<!-- overview -->
+
+This section contains information you should know before contributing new content.
+
+
+
+
+<!-- body -->
+
+## Contributing basics
+
+- Write Kubernetes documentation in Markdown and build the Kubernetes site using [Hugo](https://gohugo.io/).
+- The source is in [GitHub](https://github.com/kubernetes/website). You can find Kubernetes documentation at `/content/en/docs/`. Some of the reference documentation is automatically generated from scripts in the `update-imported-docs/` directory.
+- [Page content types](/docs/contribute/style/page-content-types/) describe the presentation of documentation content in Hugo.
+- In addition to the standard Hugo shortcodes, we use a number of
+  [custom Hugo shortcodes](/docs/contribute/style/hugo-shortcodes/) in our documentation to control the presentation of content.
+- Documentation source is available in multiple languages in `/content/`. Each
+  language has its own folder with a two-letter code determined by the
+  [ISO 639-1 standard](https://www.loc.gov/standards/iso639-2/php/code_list.php). For
+  example, English documentation source is stored in `/content/en/docs/`.
+- For more information about contributing to documentation in multiple languages or starting a new translation, see [localization](/docs/contribute/localization).
+
+## Before you begin {#before-you-begin}
+
+### Sign the CNCF CLA {#sign-the-cla}
+
+All Kubernetes contributors **must** read the [Contributor guide](https://github.com/kubernetes/community/blob/master/contributors/guide/README.md) and [sign the Contributor License Agreement (CLA)](https://github.com/kubernetes/community/blob/master/CLA.md).
+
+Pull requests from contributors who haven't signed the CLA fail the automated tests. The name and email you provide must match those found in your `git config`, and your git name and email must match those used for the CNCF CLA.
+
+### Choose which Git branch to use
+
+When opening a pull request, you need to know in advance which branch to base your work on.
+
+Scenario | Branch
+:---------|:------------
+Existing or new English language content for the current release | `master`
+Content for a feature change release | The branch which corresponds to the major and minor version the feature change is in, using the pattern `dev-<version>`. For example, if a feature changes in the `v{{< skew nextMinorVersion >}}` release, then add documentation changes to the ``dev-{{< skew nextMinorVersion >}}`` branch.
+Content in other languages (localizations) | Use the localization's convention. See the [Localization branching strategy](/docs/contribute/localization/#branching-strategy) for more information.
+
+
+If you're still not sure which branch to choose, ask in `#sig-docs` on Slack.
+
+{{< note >}}
+If you already submitted your pull request and you know that the base branch
+was wrong, you (and only you, the submitter) can change it.
+{{< /note >}}
+
+### Languages per PR
+
+Limit pull requests to one language per PR. If you need to make an identical change to the same code sample in multiple languages, open a separate PR for each language.
+
+## Tools for contributors
+
+The [doc contributors tools](https://github.com/kubernetes/website/tree/master/content/en/docs/doc-contributor-tools) directory in the `kubernetes/website` repository contains tools to help your contribution journey go more smoothly.
+
+