PDF schematic named T60PM, a ThinkPad T60 drawing where PM most likely indicates the Intel 945PM chipset version used with discrete graphics; the name gives no revision. That differs from the GM variant with integrated graphics, so confirm which board you have. The drawings help trace power rails, follow the power-on sequence, check GPU and chipset supplies and find test points. Compare the board number and revision on the PCB with the title blocks before trusting part references.
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 @schematicslaptop. 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.