Question with stamp misions

https://preview.redd.it/olsvm7yogdze1.png?width=1448&format=png&auto=webp&s=f0a52f048ff7bac92879028b93c9c61bcc77850f

Hi, I'm new to the game and I really don't understand what these mission are... Could somebody explain what are those mission and what I need to do, please