Write flow panel selections to data table

Thanks all for the useful multiple selections.
I adopted them in my form.

But my question is: when I have put all selection into the flow_panel, what to do then? I want to write the selections into my data tables.
Say I have an article table and a categories table. The categories table has just one column “category_name”. In my article table I have a “categories” column which links to multiple rows in the categories table.

In my form I have a dropdown showing the entries from the categories table. A user can select those and they show up in the flow panel like shown above. But how can I than store them in my article categories column?

Thanks for any help.

EDIT: sorry this has been I reply in another post. So obviously all the context is gone. But you can find the post where this has been split from in the link section at the bottom (“Multi Select Drop Down?”).