The extension was approved by the Board last September. All OKW contracts were extended. If you want to accept the extension you'll just need to pay DVC $15 per point - soon to be $25 per point. I believe this may all be accomplished over the phone with a credit card. Financing is also available - which would require some documents to be signed.
If you do not want to accept the extension you'll need to sign a deed over to DVC for that timeframe (February 1, 2042 - January 31, 2057). Nothing will change with your current ownership. Signing the declination documents will require a notary to verify your signature - this may be done at the SSR Sales Center.