Grapes have to be pruned every spring. You can train them any of several ways. One is in very late winter or very early spring before they attempt to leaf out is to count out 3 buds on each cane that comes out of the main stem and cut the remaining old cane off. That is the simpliest, but not always the best way in some microclimates.
Another is to train them along trellis wires like the vineyards do. That can't be easily explained in a few words. I would suggest that you go to the oregon extension site and view the doc to grape training, pruning etc. There are many other fine explanations on pruning grapes as well, but being out of the US you would have to send away for them, our cash strapped extensions are beginning to charge for all their info. So, far the oregon one still has a view feature that will allow you to read the doc. Use the net to look for grape pruning or grape care and click on the one that has osu.edu in the address. Sorry I don't know what it is off hand.