2
Use the search Luke ...
https://xoops.org/modules/newbb/viewtopic.php?viewmode=flat&topic_id=19974&forum=28
https://xoops.org/modules/newbb/viewtopic.php?viewmode=flat&topic_id=20512&forum=17
...
and finally one of my current favorites by JackJ:
xoops for dummieswhich contains the solution from one of these 2 threads and is worth a readthrough for everyone.