@zanitevI assume there must be another program for the actual coding
The "other program" is a simple text editor such as Notepad or, better, Notepad++.
Each scene is described in a file with a .scn filename extension. These files are simple text files written in what I call the "scene definition language". They do two main things
Firstly they define what external images and clips are used in the scene - this is done by a series of Texture (for images) and Clip declarations.
Secondly they define where each of these previously declared items appear. This is done by a series of nested nodes of various types (Camera, Node, Quad, Sprite, ClipSprite, ClipNameSprite and Light).
Most of these nodes can have optional "animate" clauses defining how various properties are to vary in time. This gives us the ability to move and rotate the nodes relative to each other and to dynamically vary their dimensions, colour and opacity. In the case of the camera node you can also vary the direction in which it is pointed and the width of its field of view. This is how panning, tracking, zooming fading etc. are achieved.
Further, more advanced, "special effects" can be made by using so called "fragment shaders" which are short programs written in the GSL language.
Totem only provide very basic instruction on how to do all this but some of us have looked int it in more detail much f which is described in this thread or in the two that
@Wyldanimal suggested in his post.
Many examples to study can be downloaded from his site
https://scenes.virtuastripper.netand others from mine
https://www.theemusnest.eu/scenes/Zips/