Sharing the internet connection in Ubuntu

My laptop is connected to wireless wifi and wired LAN networks. And I have internet connection on wifi network. So I wanted to share the internet from wifi connection to the computer connected to the laptop by LAN.
I have found some challange to do it on Ubuntu 18.04 so this is a reason why  I wanted to share my experience. I hope it will be usefull.

[Internet] <=> [wifi] <=[Laptop] => [lan] <=> [Wired network]

To open connections widget execute:

#: nm-connection-editor

My network interface in LAN network connected to 192.168.137.1

Lan connection settings

Wifi connection settings