FRESH INSTALL:

burn the rpi5 .img.xz from linuxcnc.org website
make sure eth0 is plugged in
log in cnc cnc
open a terminal

sudo apt update

sudo apt upgrade

sudo apt install network-manager

sudo apt install network-manager-gnome

sudo rm /etc/network/interfaces  (networkmanager doesn't use it)

you don't need to edit the file for your wifi:  (left here for those who have tried)
 /etc/wpa_supplicantwpa_supplicant.conf

 unplug eth0
Restart

CREATE A WIFI ENTRY:

menu: settings/advanced network configuration

Choose a network type -> wifi

Create

Enter SSID

wifi-security select -> wpa/wpa2/wpa3 personal

Enter password for your wifi router

Save

Restart

upper right network connections icon -> select -> Available Networks -> your router

Enter password if needed

Connect

CREATE A STATIC IP FOR MESA:
menu: settings/advanced network configuration

Choose a network type -> ethernet
Create

Device eth0

IPV4 settings -> add
Method: manual
Address: 10.10.10.1  
Netmask: 255.255.255.0
Check 'require IPV4 addressing

Save

sudo service NetworkManager restart