MSI MS-7399 motherboard schematic at revision 0A, the earliest version of this board in the index, saved as a PDF of about 1.1 MB. MSI uses the MS-plus-four-digit scheme for its desktop mainboards. The pages help trace supply rails, follow the power-on chain, and locate test points and components when diagnosing a short or dead board. Because the design was later revised up to 4.0, check that your PCB is a 0A board; parts, values and designators may differ in newer versions.
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 @pepeelectronica. 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.