Squeak is the version of Smalltalk used to build Etoys, which has its own page here in The Undiscoverable. While programming in Etoys is fully graphical (like Turtle Art, but much less discoverable), Squeak requires navigating a complex Integrated Development Environment and programming in text. There is a lot of tutorial material for Squeak, but much of the best material is in dead-tree textbooks. This page will give hints, plus links to free on-line resources.
Squeak is available in many Linux distributions. Install as usual, and invoke as usual. If there is only one Squeak image on your computer, it will open. If there is more than one, including Etoys, you will be given a choice of images to open. You will find it useful to save images containing your work. Name them so that you can remember which is which.
Install and open Squeak. You will see a welcome screen, something like this.