If you want the subdirectory to redirect to the subdomain then yes.
If you want it the other way round, ie. the subdomain to redirect to the subdirectory then install wordpress (or whatever) in that particular subdirectory.
I’d add to that that it is good practice to use different users for the main domain and the subdomain, this way if one part of the site gets compromised the other doesn’t automatically get compromised too. Though this may be a little over you head if you’re just getting started with setting up a site, on the other hand doing things right from the start is a good thing.