First you must work out whether they are climbers or ramblers - the pruning regime is different. Climbers have their main prune last week of February, or in early March if the weather is particularly cold. Long, whippy stems which haven't been tied in can be shortened in autumn to prevent windrock. All cuts should be made with clean, preferably sterilised secateurs or loppers for thicker stems - all dead, thin, weak and crossing wood should be removed. Cuts made with secateurs should be made where there is an outward facing bud, angled away from the bud downwards to allow rain to run off. Can't be more specific than that, depends on the variety of the climber and how prolific it is.