Aquire Parts and Progam your ESP8266 to Use Arduino Programming
Add a sensor. Here's a typical project, using the ESP8266 to compare a DHT11 sensor to a Bosch BME280 Sensor.
or : https://sites.google.com/d/1QXUCY-c5oviFZ9aZGh5oZ2ILApEPS0Mn/p/1mU5igM6FCLpClO2q6hPykwKfc0jRrmk9
(add a Dallas Temperature Sensor)
RandomNerdTutorials has a great selection of easy to follow tutorials, schematics, and links to parts. Project landing page: https://randomnerdtutorials.com/projects-esp8266/