diff --git a/README.md b/README.md
index b78410f..cd678e6 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ Version: 1.4.2. [Release details](RELEASES.md).
    placeholders
 6. Write your Telegram user or group ID to the `allowed_users` -> `id` by replacing dummy
    value and change `forward_group_id` value if you want to forward the video to
-   some group when upload is enabled
+   some group/channel when upload is enabled. Bot should be added to the group/channel to be able to send messages.
 7. Change download media type for the user/group: `AUDIO`, `VIDEO` or `AUDIO_VIDEO` 
    in `app_bot/config.yml`'s variable `download_media_type`. Default `VIDEO`
 8. If you want your downloaded audio/video to be uploaded back to the Telegram,
@@ -94,6 +94,20 @@ or something went wrong.
    variable.
 5. If the website you want to download from requires authentication you can use your cookies by putting them into
    the `app_worker/cookies/cookies.txt` file in the Netscape format.
+6. If your country has an [Alpine Linux Mirror](https://mirrors.alpinelinux.org/), you can speed up the image builds by:
+   1. Creating `apk_mirrors` text file and putting there your mirror urls, for example for Ukraine they are:
+      ```
+      https://alpine.astra.in.ua/v3.17/main
+      https://alpine.astra.in.ua/v3.17/community
+      ```
+   2. Adding `COPY apk_mirrors /etc/apk/repositories` to the third line in `base.Dockerfile`:
+      ```dockerfile
+      FROM python:3.11-alpine
+
+      COPY apk_mirrors /etc/apk/repositories
+      ...
+      ```
+   3. Rebuild the images.
 
 ## 🛑 Failed download
 
diff --git a/app_bot/bot/core/tasks/upload.py b/app_bot/bot/core/tasks/upload.py
index d23d73a..871ce92 100644
--- a/app_bot/bot/core/tasks/upload.py
+++ b/app_bot/bot/core/tasks/upload.py
@@ -296,7 +296,7 @@ class VideoUploadTask(AbstractUploadTask):
         try:
             self._media_ctx.thumb = video.thumbs[0].file_id
         except TypeError:
-            # video.thumbs is None when no thumnmail
+            # video.thumbs is None when no thumbnail
             self._log.warning('No thumbnail found for caching object')
         self._media_ctx.is_cached = True
         self._cached_message = message
diff --git a/app_bot/config-example.yml b/app_bot/config-example.yml
index c20dc09..84403ad 100644
--- a/app_bot/config-example.yml
+++ b/app_bot/config-example.yml
@@ -1,22 +1,22 @@
 telegram:
   api_id: 00000000000
-  api_hash: "<PASTE-HERE-TELEGRAM-API-HASH>"
-  token: "<PASTE-HERE-TELEGRAM-TOKEN>"
+  api_hash: "REPLACE-WITH-TELEGRAM-API-HASH"
+  token: "REPLACE-WITH-TELEGRAM-TOKEN"
   lang_code: !!str "en"
   max_upload_tasks: 5
   url_validation_regexes:
     - "^http(s)?:\\/\\/.+$"
-  allowed_users:
-    - id: 00000000000
+  allowed_users:  # Multiple users/groups are allowed.
+    - id: 11111111111  # User or group ID.
       send_startup_message: !!bool True
-      download_media_type: !!str "VIDEO"
+      download_media_type: "VIDEO"
       save_to_storage: !!bool False
       use_url_regex_match: !!bool True
       upload:
         upload_video_file: !!bool False
         upload_video_max_file_size: 2147483648
         forward_to_group: !!bool False
-        forward_group_id: -00000000000
+        forward_group_id: -00000000000  # Group or channel ID.
         silent: !!bool False
         video_caption:
           include_title: !!bool True
@@ -26,9 +26,9 @@ telegram:
   api:
     upload_video_file: !!bool False
     upload_video_max_file_size: 2147483648
-    upload_to_chat_ids:
-      - 00000000000
-      - -00000000000
+    upload_to_chat_ids:  # User, group or channel IDs.
+      - 22222222222
+      - -33333333333
     silent: !!bool False
     video_caption:
       include_title: !!bool True