Only the part number 2SK1897 identifies this 97.1 KB PDF, which the index places among schematics. Because 2SK is the Japanese prefix for N-channel FETs, the file should be the transistor's datasheet. It is the place to look up pin assignment, absolute maximum voltage and current, and typical characteristics when testing a suspect device or comparing it with a substitute. The manufacturer and package are not stated, so check the body marking on the original component first.
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.