Foucault was an historian/philosopher who in his Madness and Civilisation proposed that madness was mainly a construct, not its behavioural traits as the way they are perceived, which reflected the rational constructs of the Enlightenment with its somewhat fixed concept of reason. The latter owed much to John Locke, the English philosopher. His aim, in part, was to demonstrate that ultimately power lay behind knowledge.

In my own work on this subject, I focus also on the legitimising nature of madness/mental illness for psychiatry as a whole.

Algo simple:

- Elige un tema que te interese y de preferencia que sea corto. ( Michel Foucault ha escrito sobre muchas cuestiones seguro encontraras algo de tu interés)

- ¿Explicarlo correctamente? en filosofía o en ciencias sociales, prefiero particularmente que el estudiante explique las ideas relacionándolo en todo momento con la realidad, que establezca comparaciones; y si no domina el lenguaje técnico o especializado, no le quitaría valor a su interpretación, siempre y cuando sea: natural, fresca y sincera. Relajarse y pensar de eso se trata al inicio.

My approach would be to find a good secondary source to begin with. For example something from the Stanford Encyclopedia of Philosophy:

https://plato.stanford.edu/entries/foucault/

If you find a text or an argument there that you are interested in, you will usually find further sources related to that text or argument.

As a general rule in analytic philosophy, take a small text or argument and show how it works in detail and as clear as possible. Avoid any unnecessary complications.

As an alternative, you could treat it as history and just do a report. Hope that helps (and it is not too late).