Portuguese PDF, 88.3 KB, on using a bench power supply (fonte de bancada), apparently converted from another document format. No device or model is referenced. Such guides typically explain setting voltage and current limits, connecting leads, and reading current draw. In repair work, a bench supply with a current limit lets you power a board safely, spot a short from abnormal current, and inject voltage to heat up a shorted component. Set the limit low before connecting to avoid further damage.
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 @canalesquematicos. 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.