how would i go about changing my automatic transmission to a manual transmission in my 98 buick century

thank you, very helpful ill keep updated s on whether it works or not.

Possible but very expensive to add all the parts your car didn't come with like, clutch peddal & floor shifter kit (like Hurst), linkage & hydralic slave cylinder, transmittion. cross member trans mount, bell housing, clutch disc, pressure plate, flylweel throw-out bearing assemblies, cabes & computer connections, all nessesary hardware. And a different length driveshaft? Yours might be able to be shortened if too long, & or lengthened & re-balanced if too short by a driveline specialist. Auto transmittons are always longer, manual trans are shorter. A cool upgrade would to be add a tachometer like a black face illuminated Stewart Warner.