Use the [Letsencrypt container](https://hub.docker.com/r/linuxserver/letsencrypt/), it has already pre-configured `.conf` files for subfolder and subdomain to make is easy.
Use the [LinuxServer SWAG container](https://hub.docker.com/r/linuxserver/swag/), it has already pre-configured `.conf` files for subfolder and subdomain to make is easy.