Number of authors in citations style LibreOffice


I am trying to set the number of authors appearing in the citation of an entry in LibreOffice document. In the jstyle file fields MaxAuthors or MaxAuthorsFirst (i don’t understand the difference between those two by the way !) does not change anything in the display in LOWriter. I want to have a citation like this [Author1 et al, YYYY] with only the first author then ‘et al’ in italic and the year field. Is there any help to do so ?