Arduino Leonardo with ESP 8266 12E without USB to serial converter

Hi, I have an Arudino Leonardo with an ESP 8266 12E WiFi module, can anyone tell me what is the correct wiring to connect the two modules without using an USB to serial converter?
Thank you.

use the SerialPassthrough sketch from examples. change the baud rate in sketch to 115200.

wire esp8266 to Serial1.