Hi Mikkel

You should be able to do it with the CData Excel Online provider.
You will most likely need to create a custom OAuth app.
http://cdn.cdata.com/help/FXE/ado/pg_oauthcustomappcreate.htm

Or if not possible

Excel Services.
http://cdn.cdata.com/help/DTE/ado/

Sorry to say but the directions are almost unreadable for a non-expert. 

Can i contact anyone at your end for an introduction?

Hi Thomas 

Have you tried this yourself?
Could you share a short documentation on how to set this up?

Hi Andri
These are the settings I use for Excel Services.
 

I only point to and sharepoint URL and then has a file to connect to. The difficult part is figuring out what the folder structure is.

Hi Andri

Here are the settings I use for Excel Online.
 

I use an app to connect to my files stored in OneDrive, which is also stored in an SharePoint.

Has there been any more formal process documented by TimeXtender (or anybody) on this process?  I have excel files in SharePoint online that I need to pull into TX and I am green on exactly how this is done.  I don't even know why I would use one (excel services) over the other (excel online).  I need this dumbed down.  If the posts above are dumbed down, I need it even dumber.

We have three guides for Excel regarding CData.

And if you are using the 20.10 release.

https://legacysupport.timextender.com/hc/en-us/articles/6266451214749-Excel-with-CData