Learn French: La chorégraphie dont je parle a des pas très complexes. - The choreography that I am talking about has very complex steps.

The verb parler takes the preposition de when you talk about something (parler de). In French, when a relative word replaces a phrase starting with de, you must use dont. In this sentence, it works like saying the choreography 'about which' I am talking.

Does the word pas always mean 'not'?

No. While you often see pas making a verb negative, here it is a noun meaning a physical step or a dance step. Because the singular word un pas already ends in an s, its spelling stays exactly the same in the plural as des pas.

Why is it des pas très complexes and not de pas très complexes?

When an adjective comes after a plural noun, you use the standard plural article des. The article usually only drops to de if the adjective comes before the noun, like in de beaux pas.

Why are there two verbs right next to each other (parle a)?

They belong to different parts of the sentence. The verb parle belongs to the descriptive chunk dont je parle (that I am talking about). The verb a (has) connects back to the main subject, La chorégraphie.