Here is a link to the instructions, it's very simple as other members have pointed out.
https://www.collegehillshonda.com/instructions/civic/2023/tailgatespoiler.pdf
No, it is currently in transit. If you would like the point-of-contact at that dealership, feel free to PM me.
EDIT: Didn't see that you already have an FL5.
I agree. Whenever the subject of oil comes up, there always seems to be a lot of brand-loyalty, placebo and psuedo-science like you stated.
If they really wanted to see a quantifiable, measurable difference in different oils and oil change intervals, they would send their used oil in for analysis.