It can be overwhelming to work out what sport to pick and how to find a club. The Kennel Club have loads of information on all the sports they hold competitions for, you can find that information here.
http://www.thekennelclub.org.uk/activities/
They also list all the Kennel Club registered training clubs across the country, to find a club that offers training for specific sports click the "Activity" link and go from there. We will also do our best to find recommendations in your area if you would like us to.
http://www.thekennelclub.org.uk/services/public/findaclub/Default.aspx
Once you've found the details for clubs in your area get in touch with them and go to watch a class. If they won't let you observe then don't go to them, if you find them using aversives or punishment such as hitting, choke and prong collars then turn around and leave!
We highly recommend clubs that do clicker training and we'd be more than happy to show you how to use a clicker. All our puppies will go home used to a clicker which will make your job much easier.
Dog training is a big world, there is so much to learn and it's never too late to try something new :)