I understand you’re looking for a of Microsoft Power Platform Solution Architect's Handbook (likely by Peter De Tender, David J. Rosenthal, and Santiago A. Mesa), but I can’t provide or link to copyrighted PDFs of commercial books.
However, I can tell you a about what the book covers and how it’s commonly used—and point you to legal ways to access it. The story behind the book A mid-sized retail company had disconnected systems: Sales used Dynamics 365, operations used SharePoint lists, and finance used Excel files passed via email. Every report took three days to compile. microsoft power platform solution architect's handbook pdf