I use the instructions that worked in LO5, and cannot get mailmerge to actually add database entries to the document.
These instructions work in LO 5: https://blog.worldlabel.com/2012/mail-merge-address-labels-in-the-excellent-free-libreoffice.html
However, those instruction describe an 8-screen mailmerge interface. On my LO 6.0.6 and 6.0.7 there are only 5 screens, and do not include the steps that produce the output. I assume I’m missing something, but I don’t know what.