How to install lets encrypt certificate for pfsense router GUI

First of all thank you for a quick response.
I have the netgate router running pfsense 2.4.3.
I install the package acme, created the the account key and register the key.
Problem I have is to create the certificate.
The domain is required which in my case is the localdomain.
And what method should I use( standalone webserver, web root local folder)?
Finally how and were do I enter the txt file?
Is there a good guide for doing this?
Also I run webserver on dmz were I host few domains. I was able successfully setup certboot for those domains. But don’t know how to do this for the router GUI.

Thanks,