contribution guidelines

.github/ISSUE_TEMPLATE/locale.yml

@@ -0,0 +1,17 @@
+name: Locale Issue Report
+description: Report a locale issue
+labels: [localization]
+assignees: []
+body:
+  - type: markdown
+    attributes:
+      value: |-
+        Do not use this form to request new languages, new languages can only be added if someone opens a PR. Refer to [Contributing Locale Updates](https://github.com/KatsuteDev/Background#contributing-locale-updates) for steps to add a language.<br><br>
+
+  - type: textarea
+    attributes:
+      label: Issue
+      description: |-
+        Explain the issue.
+    validations:
+      required: true

README.md

@@ -122,6 +122,14 @@ Use the <kbd>Background: Configuration</kbd> command or press the **Background**
 
 ## &nbsp;
 
+### Contributing Locale Updates
+
+Translations from online translators not accepted.
+
+Locale files must use the language name in <https://code.visualstudio.com/docs/getstarted/locales>.
+
+Copy `package.nls.json` to `package.nls.{language}.json` and replace only the values, `{#}` is automatically replaced in the extension.
+
 ### API
 
 Add this extension to your `package.json`.