Once logged in, go to your profile. You can choose the skill you would like to test, among the 16 available.
Then, you answer the questions. You can only validate your answer once: it isn’t possible to go back after validating your answer. If you don't know an answer, you can skip the question. You can interrupt your test and pick it up where you left off, using the "Resume" feature.
Once you have completed your test, Pix will show you your score for this skill, and the answers to the questions you’ve been asked. You can then choose another skill to test and repeat this process.