The general idea of STARKs is to transform a claim on a certain computation to another claim on the low-degreeness of one polynomial. This construction has gained a lot of attention during the past year, leading to several implementations in the wild. During this talk, we will explain how to build a STARK using genSTARK, one of these libraries. We will also share its complexity analysis based on the different parameters involved in Pedersen commitments computation, assuming very little mathematical background. Only some basic cooking notions will be expected from the audience. I will do a 30min rehearsal for my talk at the ZKProof Community Event in Amsterdam on October 29. This is a presentation of the summer internship I did at QEDIT, Tel Aviv.