GROUP multiples or NOT?


I am working around a concept for a city indoor playground
HOPING (if I can learn UE5.03) to take it there.
I am wondering I have a problem with Datasmith exporter and SKU
I installed the plugin and after using the only button there is “export”
it always gives me my file name.datamsith but NOTHNG in the file format
I have un and re installed it x times and always the same issue!
Very frustrating as on youtube it seems everyone only shows how to export
through Datasmith plugin.
Very few show other options
I found one that explains how to only safe the groups as .fbx
OK so I wanted to go that way.
But when I take my whole playground I get nothing I can work with
in UE5 as a beginner
So I saved all the content /asset groups separately next to my two floors

Now I would like to ask the groups are already groups in the whole building
I only copied each to the side to hopefully start with a few import as .fbx

What I don’t understand and seem to get lost is
Are my groups now listed two times must I delete one of the two
or merge them in the group window?

I manged to create the simple volume of the two floors walls and doors and basic floors
in UE 5 but now to bring it all from SKU 19
still is a mystery.

I wrote to UE and the replied and advised to unstall and reinstall
but I still get the same file name with NO file type (simply and empty line )
Naturally I tried to click and see if I forgot to show that file type
but there is NO choice at all when I try to open that file
after the exporting NOTHING remains in the file explorer (WIN)
that I can see and import on the other side.

Thank you.