Summarize:

Choose two canes that are roughly the same thickness as your pinky finger. Ideally, they should grow as near to the head of the vine as possible, and the buds should be close together. The "head" of the vine is the point at which the trunk intersects with the top wire of your support system. The two canes should be positioned on either side of the trunk. These two canes will be your primary canes. During the following season of growth, they will grow new shoots that can bear fruit. Selecting canes close to the trunk head prevents the arms from becoming too long. Excessively long arms can create nonproductive gaps in the vine. Make sure that your chosen canes have firm wood with a brown outer layer of bark nearly all the way to the tip. They must not have any visible damage, either. Prune your two chosen canes down so that only 8 to 10 buds remain. Tie the remaining portions of both canes to your support system. Choose four additional shoots that are thinner than your two primary canes. Trim these down to two buds each. These spur canes will act as sources of renewal during the following year's cane production. These shoots should all be close to your primary side canes. Remove any other cane not already selected by cutting it away at trunk level.
Select one or two canes. Trim the canes down. Set aside one or two spur canes. Cut away the rest of your canes.