ESPurna ("spark" in Catalan) is a custom firmware for ESP8285/ESP8266 based smart switches, lights and sensors.
It supports a number of SONOFF devices and feaures e.g. MQTT and Home Assistant integration.
You may find more information on github.
Beware that it requires effort and IT skills to configure and integrate ESPurna devices with home automation systems. This is not products for novices.
It provides local control, MQTT and integration with home automation systems such as openHAB, Home Assistant and Domoticz.
You may find more information on the official GitHub page
If you are starting out and wish to have a relatively easy experience in developing your projects, then try the build-in web interface.
Example of Tasmota Web Interface
the Sonoff 4 Channel Pro MQTT Switch
On delivery it is already in factory reset state.
If you want to factory reset afterwords, check this link Tasmota Button Usage
When held continuously for 40 seconds (Configurable with SetOption32, value is 10x the configured hold time) Tasmota will reset to firmware defaults and restart.
For the temperature/humidity monitor, you also need to specify the sensor type, e.g. AM2301.