+user63652 there's such a lot going on in ICC that it is difficult to give a short answer. Rides are advertised usually a few days in advance on the forum here http://forum.islington.cc/microcosms/114/
Generally new riders are encouraged to join one of the Sunday club runs where there are rides starting from 30 to 40 miles. The club has a strong emphasis on group riding and it is essential new riders understand group riding techniques.
A helpful overview on group riding can be found on the GCN website https://www.youtube.com/watch?v=QPXijIKgFVM&feature=youtu.be