Hello! Similar to the home automation tutorial..
I would like to use MQTT to communicate between an ESP8266 connected to Adafruit’s “Neotrellis” 4×4 with a Rpi using mosquitto/NodeRed without the use of the internet or a router. I am a bit confused on where to begin. In the past I have successfully controlled relays using mqtt with a pc/esp’s over wifi.
So I know how to setup MQTT, how to program an ESP using arduino IDE.  How to control a relay/write flows using NodeRed.
Where I need help is…. 
How to program the Esp8266 to control the Neotrellis with NodeRed?
Best way to setup Client-Server WiFi communication between esp8266 and Rpi?
Do I make the esp the server and have the pi connect using this tutorial…

ESP8266 Client-Server Wi-Fi Communication Between Two Boards (NodeMCU)

 
Thank you so much for your time!  I appreciate the help!