Thank you very much Gareth Barnard,
I have reviewed by reviewing the code of the page and I have found that its course format is "Board Format", I looked for it in moodle plugin and I have found that format but when installing it on my platform the format is different, I think that they have edited the format taking it only as a base.
Is it possible to modify the "HTML" of a course format? If possible, could you guide me on how to do this? I have browsed through all the .php files of a format but I can't find its "HTML".
Greetings.