As reported here, it looks like sometimes the default star registration is set to “One star registration”, instead of “Global star alignment”. I don’t know if the change comes from a different build (it was reported from a MacOS build) or more likely from a previous use of the program (if you select another registration algorithm, on the next restart of Siril the selected algorithm is last one you have set).
So, the article we should precise the algorithm to be used. Instead of "
we should write something like “4. In the Register tab, select Global Star Alignment (deep-sky) from the registratrion method drop-down list and click Go register.”