What is a match in an elasticsearch query?

Question

PHP

Good day to all.
For several days I have been tinkering with the devil named elasticsearch
. It doesn’t work for me at all. More precisely, I index the document (or the docx file using ingest-attachment) and even do a search, but I can’t find a normal description of what a query is, what a match is anywhere. In which case match-all or just match should be written and how to compose a search query in general. I don't understand the point.
I did not find anything normal in the elastic documentation. In the documentation in Russian on codezen, there is also nothing sensible specifically for these parameters.
Please tell me where all the necessary parameters are normally described search
PS
If you want to tell me something like "you're just not smart enough to google" or insult me ​​in any other way, then just don't help and move on. I googled a lot and google now, but maybe due to inattention or something else, I just did not find the necessary information.
Thanks in advance
Example

$query = [
        'multi_match' => [
            'query' => 'test',
            'fuzziness' => 'AUTO',
        ],
    ];
        $searchParams = [
          'index' => 'ingest_index',
          'type' => 'attachment',
          'body' => [
              'query' => $query
            ],
      ];
      $x = $this->obj->search($searchParams);