More than 25 years after the formation of ultracold molecules at Laboratoire Aimé Cotton in Orsay, the first molecular Bose-Einstein condensate (BEC) was created last year in 2024 in the USA. To achieve this, the experimental team used a microwave shielding technique between two molecules. As in atomic BECs, collisions between three particles are also important to understand. This Master 2 internship will consist of theoretical and numerical investigations on three-body interactions of the molecules in the presence of the microwave. We will determine the conditions under which three-body protection can be efficient.