I would like detail how to change wiper blade assembly on a 1990 magna.Can anybody help.

you may have to open the bonnet
the whole blade is on a spline
you undo the nut at the arms base
then gently take the wiper blade arm off the spline
try not to scratch the paint

Fitted the blade holding section of arm from a 3rd gen to the splined section of arm on my sons TP once. All clipped together no probs.

Cheers