"To know the details" means to have specific and comprehensive knowledge about a particular subject or situation. It implies being aware of specific facts, information, or specifics rather than having a general or vague understanding.
Sentences with «to know the details»
But many people struggling with their finances don't know the details of how their money works. (personalprofitability.com)
How is it possible a firm can spend that much money and you don't know the detail of what the firm is doing? (patrickjlamb.com)
We still don't know details about it, but the modifications will lead to drop in overall weight. (suvtrend.com)