hi I want to backup my mastodon account and am trying to set a more useful custom filename to download my likes/bookmarks. I would like it to be instance_username_date_(media id)_number.extension. I barely have any coding experience, so the documentation unfortunately isn't very helpful to me. I copied the default config file and frankenstein'ed some stuff I saw other people post. It is now like this:

"[instance]":
{
"root": "[instance]",
            "access-token": "[my access token]",
            "cards"       : false,
            "reblogs"     : false,
            "replies"     : true,
            "text-posts"  : false,

"postprocessors": [{
"name": "metadata",
"event": "post",
"filename" : "{instance}_{author[name]}_{date:%Y%m%d-%H%M%S}_{media[id]}_{num:?/ />02}.{extension}",
"format": "{content}\n"
}]
        },

So far my test files turn out like this
[instance]_110924171079948278_110924150688849789.jpg for images (the default file name)
[instance]_None_20231129-163556_None_.None for image descriptions

I would be eternally grateful if somebody could tell me how to fix this 🙏