Service manual for the Samsung Galaxy A51, model SM-A515F, in a 34.7 MB PDF; the name is in Spanish. Samsung service manuals generally cover disassembly, exploded views, parts lists and schematic or layout sections for the mainboard. A technician uses it to locate components, follow power and signal paths and plan safe teardown and reassembly. Any PDF reader opens it; check that the device carries the SM-A515F code, since other A51 regional models differ in RF and some board sections.
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 @esquemaseletricos. 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.