All grapes produce fruit on one-year-old wood. That means that the growth produced during the previous year will produce fruit for the coming season.
After planting, do no pruning at all during the first full year. Immature grape vines need abundant stems and leaves to help develop a strong root system.
The second year, select the strongest and most vigorous stem that developed during the first season. Remove all other stems and leaves as close to the base as possible. Stake the one remaining stem to provide support. This stem will become the main trunk of the vine. Pinch the top of the main stem to encourage side growth.
After the second year, select two of the best-looking stems that are growing horizontally from the main trunk. Ideally they should be on opposite sides and about the same height on the trunk.