The trigger phrase for the applet is awkward, I have to say "Ok Google, DayOne Journal [what am I doing]" all in one sentence. I can not change the trigger phrase like "Ok Google, Journal" and then do something.
I cannot edit the applet that I found, so I created my own. The trigger phrase is "Ok Google, log $" or "Ok Google, journal $" and then the assistant will confirm that it is entering this in my Day One journal.
The cool thing about this is that I can now create quick entries in to my Day One journal using my Pixel 2 phone and my Fossil Q Explorist.