Using WordPress for both a domain and its subdomain

I’ve created a static site using WordPress. Now that it’s running, we’d like to duplicate the site translated in french. We created a subdomain: french.ourdomainname.com. T

The goal is to have visitors go to the main website and then link them to the subdomain if they want the french version, while allowing them to also link back to the english version of the website. Basically, we’d like to run WordPress for both the website http://www.ourdomainname.com AND the subdomain french.ourdomainname.com.

If it is possible to run WordPress for both the website and its subdomain, can you provide me the proper steps to set this up so that it works smoothly for both.

Thank you so much in advance.