I am trying to follow the beautiful notes by Peter Scholze on condensed mathematics (https://www.math.uni-bonn.de/people/scholze/Condensed.pdf)

I am noting that the hard time that I am getting is a lack of basis in Grothendieck topologies, sites, and so on, things that are not from the theory of condensed math itself but prerequisites.

So I would like to know if is there a standard book, or nice notes used for the introduction on such matters, with more concrete examples of the objects defined.

Thank you very much for any suggestions.