chore: Update README

README.md

@@ -1,10 +1,10 @@
 # yt-dlp-FixupMtime
 
-A [yt-dlp](https://github.com/yt-dlp/yt-dlp) postprocessor [plugin](https://github.com/yt-dlp/yt-dlp#plugins) which sets the mtime of all files to a given datetime value by key.
+A [yt-dlp](https://github.com/yt-dlp/yt-dlp) postprocessor [plugin](https://github.com/yt-dlp/yt-dlp#plugins) that sets the mtime of all files to a given datetime value by key.
 
-This postprocessor does not support all possible files output by yt-dlp, namely `*.dump` files.
+Some file types (namely `*.dump` files) that can be optionally output by yt-dlp when downloading are not supported.
 
-NOTE: This postprocessor should not be run before files are downloaded.
+NOTE: This postprocessor should not be run before files are downloaded. The default `when` value of `post_process` is recommended.
 
 ## Installation
 
@@ -21,14 +21,16 @@ See [installing yt-dlp plugins](https://github.com/yt-dlp/yt-dlp#installing-plug
 ## Usage
 
 ```text
---use-postprocessor FixupMtime[:;[mtime_key=<key>][mtime_format=<format>]]
+--use-postprocessor FixupMtime[:[mtime_key=<key>];[mtime_format=<format>]]
 ```
 
-Where `<key>` is the key of your desired datetime within the infojson dictionary and `<format>` is the format of the datetime.
+Where `<key>` is the key of your desired datetime within the infojson dictionary and `<format>` is the [format](https://docs.python.org/3.7/library/datetime.html#strftime-and-strptime-behavior) of the datetime.
 
-The default value for `mtime_key` is `mtime`, which will set the mtime of all files (thumbnails, subtitles etc.) to the existing mtime of the video. If `mtime_key` is `mtime` and `--mtime` was passed to yt-dlp at the time of download, the value will be the datetime of the last-modified header.
+The default value for the `mtime_key` parameter is `mtime`, which will set the mtime of all files (thumbnails, subtitles etc.) to the existing mtime of the video. If `mtime_key`'s value is `mtime` and the `--mtime` option was passed to yt-dlp at the time of download, the value will be the datetime of the last-modified header.
 
-The default value for `mtime_format` is `%Y%m%d`. The postprocessor will also attempt to guess the format with yt-dlp's internal list of formats.
+The default value for the `mtime_format` parameter is `%Y%m%d`. The postprocessor will also attempt to guess the format with yt-dlp's internal list of formats.
+
+Both parameters are optional and can be specified in any order.
 
 ## Examples
 
@@ -49,3 +51,12 @@ Set the mtime of all files using a custom datetime and format:
 ```text
 --use-postprocessor FixupMtime:mtime_key=meta_date;mtime_format=%Y-%m-%dT%H.%M.%S
 ```
+
+You can combine multiple invocations, ordered from least to most preferred:
+
+```text
+--use-postprocessor FixupMtime:mtime_key=upload_date
+--use-postprocessor FixupMtime:mtime_key=release_date
+--use-postprocessor FixupMtime:mtime_key=timestamp
+--use-postprocessor FixupMtime:mtime_key=release_timestamp
+```