Once this is done, you can launch Scribus and have a first try.
Activate the Insert Render Frame tool (fourth icon in the toolbar or use the D key) and draw a frame on the page, in the same way that you would do for any other frame. After a little "rendering" time, you will get a sample content in the frame.
This content tells you what to do: right-click and select Edit Source.
You'll have to then choose which render engine to use by selecting form the available engines in the Program list.
And finally, feed the render engine with some lines of code, according to the program chosen. This can be done in the Editor window.
The source window will display the code used to generate the content of the frame. This source code is specific to each external render engine. The one we see first is LaTeX, but if you change the selected program in the Program list, you'll see samples for each. On the right-hand side of the Editor window...