Schematic PDF of 328 KB whose name, 8CLJQ045, reads like a component or part code and gives no laptop model, brand or board number. The small size suggests a short document, perhaps a single-part datasheet or a partial circuit rather than a full motherboard schematic. Open it in any PDF reader and confirm what it covers before using it. If it describes a component, compare the marking on the actual part and use the pinout and application circuit to check supply pins, outputs and expected voltages during diagnosis.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.