How to get serial communication between Arduino Due and ESP8266 D1 Mini?

I'm new to Arduino but I want to have a serial communication between Arduino Due and ESP8266 D1 Mini so that ESP8266 Wemos D1 mini sends data to Arduino Due.
I tried RX/TX - TX/RX, I tried SoftwareSerial (doesn't compile on Due)., I tried Serial.read/write and Serial1.read/write. Nothing works. There are no examples either.
What is the best way to send data from ESP8266 D1 Mini to Arduino Due? If anyone has had the same issue and solved it, please let me know. All the help is greatly appreciated.

use Serial1 (RX1, TX1) on Due. wire TX to RX (transmit to receive). don't forget to wire ground. use same baud rate on both sides