This section is teaching the near past/near future which is used frequently in French to describe events that either recently happened or are about to happen. The format for the near past in French is subject + conjugated venir de + an infinitive verb.
Je viens de lire. / I just read.
This particular construction is also present in Spanish: "Venimos de comprar los vestidos" could mean we are literally coming from buying the dresses, or it could mean that we bought them a very short time ago. Apropos of that, how would you say "We came from buying the dresses" or similar, in French?