Part number 2SC4223 is all the file name gives, so this 93.9 KB PDF is best treated as a datasheet for that component rather than a circuit schematic. The 2SC prefix follows the Japanese JEITA convention for NPN bipolar transistors. Such sheets usually list collector-emitter voltage, collector current, power dissipation, hFE ranges and the mechanical outline. Before relying on it, match the marking code on the actual part, because small SMD packages often carry abbreviated markings instead of the full type number.
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.