Hi @Ismail Cassiem ,
Welcome to Microsoft Q&A!
You should create 2 dimensions to join 2 fact tables, because you said the same source aggregated at different levels. Please refer to this thread to get more details, see below:
Your dimension is represented by the surrogate key in whatever facts it applies to, so it should be the surrogate key that appears in fact 2.
I didn't spot the point of your question, originally, where you mentioned the 2nd fact was of a different grain. The dimensional way of doing this is to have a second dimension at that higher level, which only has columns appropriate to that grain. Both dimensions are 'conformed' in the sense that the titles and contents of the fields align.
Best regards,
Carrin
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