how do I install a Samsung ml 2525 driver on a Mac Pro?

What macOS version do you have?

The latest drivers only support as high as 10.13.

https://support.hp.com/us-en/drivers/selfservice/samsung-ml-2525-laser-printer-series/17156979

have you tried resetting the printing system, installing the latest drivers and try adding the printer

Is your model a USB connection or network?

This page at HP suggests that printer was supported at least through through 10.13 High Sierra and provide a download of "Samsung easy printer manager" software.

https://support.hp.com/us-en/drivers/selfservice/samsung-ml-2525-laser-printer-series/17156979

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