Mine came already installed in my A1200, so I don't know the exact installation instructions for the A1260. Maybe you can find those instructions still on the Internet, as well as disk images (.adf or .dms) of any installer that might have been provided with the accelerator when it was new.
You will definitely need the correct libraries for the 060 installed to your hard drive before you install the A1260, but there might be a couple of other items you may need.
Did you get the SCSI add-on as well with it? I think it is a great card and love having 256mb RAM inside my A1200. It is maybe my favorite Classic Amiga now.
