In order to get access to the data you need to be registered to the database. You can follow the directions given at "how to access data" within https://earth.esa.int/web/guest/-/proba-chris-level-1a-1488 website. You need to be registered to My Earthnet in order to continue. If you haven't registered to My Earthnet, you can use the link given on the upper right corner of the website.