How to get tags into the converted ugoira and how does tag and metadata works?

[pawfmrpimt]

I created this script from the doc and examples config although it's a bit confusing but what I wanted to do is First extract images and ugoiras at original quality then convert ugoiras into mkv lossless files with tag set at "original" and metadata to "true". I have the problem with finding tags or metadata on both video and image so where does it store the tags and metadata to? Also whats the best ffmepg config for mkv lossless and quality?
The code:
{
"extractor": {
"pixiv":
{
"metadata": true,
"postprocessor": ["ugoira-copy"],
"tag": "original",
"ugoira": "original"

    }}

"postprocessor": {
"ugoira-copy": {
"name": "ugoira",
"extension": "mkv",
"ffmpeg-args": ["-c", "copy"],
"libx264-prevent-odd": false,
"repeat-last-frame": false
}
}
}

[pawfmrpimt]

I have a problem apply the following config file to gallery-dl located at /Users/name/ .config/gallery-dl/ what command do I need to use to apply it to gallery-dl or how do I use options command like -o and other command to do what I asked in the first post?