How to change the title is not explained
You say, "likewise, modify the rest of the headings". Is the learner expected to modify one cell at a time? Do you show elsewhere, possibly in some other tutorial, how all changes can be done in one go?
LibreOffice-Suite-Calc-6.3 Introduction-to-LibreOffice-Calc 14-15 min 0-10 sec
How to modify column titles is explained from 13:15 onwards in the same tutorial.
Specifically, in the video at 14:06, the cursor selects the "Format Painter tool" and easily replicates the formatting in all the subsequent cells.
Hope this helps.