In the syntax `-map 1:a:24`, `1` stands for the input file index. Counting starts from `0`, so `1` refers to the 2nd input file but the command only has one input. `a` stands for stream type, and in this case, it's audio - `v` is for video, `s` for subtitles, `d` for data. `24` represents the 25th (0-indexed, remember) audio track. If your command has one input file with three video, three audio and three subtitle streams in the following order: `V A S A V S V A S`, then the 2nd video will be `-map 0:v:1` You can reference it using absolute index by using `-map 0:4`. With absolute indexing, there's no stream type specifier.

Assuming the stream numbering in your description is correct, use

    ffmpeg -i IN.MKV -map 0:0 -map 0:a:0 -map 0:a:2 -map 0:s:23 -map 0:s:24 -c copy OUT.MKV

Note that if `-c copy` is omitted, all streams will be re-encoded - not what you want normally.