Convert communication to team site sharepoint

M365Specialist 

I tried as you suggested, and clicked the "Classic change the look options".  

I then selected a generic theme, and it then asked me to choose between site layout style Seattle (which appears to have the left hand navigation showing) and Oslo.  

I chose Seattle, and clicked Try it out, and then confirmed on the next page.  

However, there is no left-hand navigation bar showing for me when it applies the changes.  The lists are still showing on the top of the page, spread horizontally.  I have to click the 3 dots to get all the lists to show. 

There must be a step missing somewhere that isn't allowing the use of the left-hand navigation tab.