The name SDLS175 identifies this 515 KB PDF only as a document code, not as a particular part. Texas Instruments uses SDLS literature numbers for its standard logic datasheets, so read the first page to find the exact device. Such sheets give pin assignments, function tables, propagation delays and absolute maximum ratings. On the bench, they let you confirm power and ground pins, judge whether measured outputs follow the inputs correctly, and pick an equivalent part with identical footprint and logic function.
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 @datasheet_technar_org. 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.