Schematic whose name only gives S22, MB and VB, so the brand, model and revision cannot be determined from it. The 1.14 MB PDF should contain motherboard circuit pages. Before using it, compare any project code and revision on the PCB with the title block inside the document. Once matched, it serves for tracing power rails, checking enable and power-good signals, locating components by reference designator and identifying test points during no-power or no-boot 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 @ITHINKHS. 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.