A few years ago we helped to clear up an allotment that had been completely overrun by four or five vines. They had not been pruned for about 10 years and were completely impenetrable. I did lots of research about the best way to renovate/prune vines but none were much help because they were aimed at commercial growers who needed maximum yield.
In the end we just cut off all the growth that could be dealt with by a good set of sharp secateurs. We did not check how many buds there were, or whether it was a lateral or not. The vines looked pretty devastated when we had finished but, come the spring, started shooting out new growth like there was no tomorrow. They produced a huge crop of grapes which were shared by all the allotment holders. I have come to the conclusion that it is almost impossible to kill a vine by pruning. it will always produce some fruit, providing it gets enough sunshine and warmth.
As each year goes on you become better at the pruning but, to begin with, just have a go with the secateurs. You can't go far wrong.