Small PDF of 544 KB with a purely numeric name, 1720524, that gives no hint about the brand, model or board it belongs to. It is catalogued as a schematic, but the content could equally be a datasheet or a few pages of a circuit; open it in a PDF reader to identify it. If it proves to be a board diagram, use it for following supply rails and signal paths and locating parts, but first match the board number and revision printed in the title block against those on the PCB under repair.
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 @one5technology. 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.