Create a simple Ubuntu VNC server in your LAN

Install minimal Ubuntu server with SSH, connect to it and:

sudo apt update

Install simple GUI:

sudo apt install -y xfce4 xfce4-goodies

Install VNC server:

sudo apt install -y tightvncserver

First run it:

vncserver
# enter password

Kill it for now, more configuration is needed:

vncserver -kill :1

Edit config:

vi ~/.vnc/xstartup

add

startxfce4&

and delete everything else
Run again:

vncserver

connect via vncviewer (sudo apt install tigervnc-viewer on Linux client) to the following host:

x.x.x.x:1

to change resolution:

sudo vim /etc/tightvncserver.conf
$geometry = "1600x1200";

And restart:

vncserver -kill :1
vncserver

Another way is to pass -geometry 1600x1200 as commandline option to vncserver:

vncserver -kill :1
vncserver -geometry 1600x1200

For clipboard sharing - on VNC server:

sudo apt-get install -y autocutsel

and add to ~/.vnc/xstartup the line before XFCE startup:

autocutsel -fork

And restart VNC server:

vncserver -kill :1
vncserver