I'm not sure what you're trying to show - currently it looks like the line graph and bar graph are displaying the same info.
Second, that kind of viz is a bit chaotic and I believe Drummey did it to show it was possible, but not necessarily a visualization recommendation.
You can download his workbook to dive into it, however: https://public.tableau.com/views/barsandlines/Introduction?:embed=y&:display_count=no&:origin=viz_share_link
Thank you for the quick reply. I will look at Jonathan Drummey's workbook and try it out on my data.
What I ultimately need to do is show an average trend line for each of the variables in the bar charts. The trend line should have a separate "Date Aggregator" that only controls the trend line. The bar chart will also need to have a separate "Date Aggregator". Do you know if this is possible in Tableau? I created another post in the forum for this question: How do I have separate date groupings for each chart in dashboard?
Thank you again for your help Bryce!