Add remote ESPHome integration behind firewall

Hi guys!
I am newbie about HA and ESPHome so I lost some time about adding ESPHome integration to HA.

I am using remote DS18B20 temperature sensor on ESP32 board connected to 4G router hotspot, sending data to Home assistant.

I suppose almost all users here are already expert about this, if not and if somebody interested I could share my code and my router settings.