There are three ways that I know to install Scratch on the Lubuntu Linux System. The first is using Wine, the second is with Snaps’ Linux and for last using online version.

Unfortunately Scratch 2 just works online, because the Adobe AIR it is no more supported by current version of linux.

Installing Scratch 1.4 with Wine

First you need install Wine:

$ sudo apt update
$ sudo apt install wine64
$ wine WINEPREFIX

Then download the windows installer and execute it.

http://download.scratch.mit.edu/ScratchInstaller1.4.exe

$ wine ScratchInstaller1.4.exe

Instaling Scratch Berkely Snap

Using this option you will need install snapd.

$ sudo apt install snapd
$ sudo snap install berkeleysnap

Now open the browser and access the app with http://localhost:8081. In Chrome you can press F11 key to full screen.

Scratch 2 online

There is also a online version of Scratch 2. Acesse in:

https://scratch.mit.edu/projects/editor/

Watch my tutorial on Youtube

If someone knows other way tell me please! Good codes for you!