MyBB Community Forums

I would like to import a custom forum into mybb. 
I can create a csv file with all the custom forum data. 
Is there any way to import it into mybb? 
What data must the csv file have? 
Thanks

What is a CSV file please Explain

A file like those used by excel where fields are placed in each column and row

Forums are using multiple tables with relations between them, so you can't import a simple csv file.
The merge procedures are complex because they must know how to translate datas from sources to target, and flat files can have too much designs to be simply imported.

You'd have to write a merge system module. There's no way to just import CSV files.