00:30 - dataset availability at course moodle page or at https://doi.org/10.5281/zenodo.7348378
01:00 - tarif excel table
02:55 - field calculator
04:20 - "exp" is the exponent operator - you can search for it using the search window on top of the middle panel 
07:00 - conditional CASE ... END expression to apply three different equations depending on the value of "tarif" column.
09:00 - styling points using the new volume column