There are diverse opinions on pruning. Some will say “don’t bother” and yet it is such a fast growing vine, you will need to eventually do some minor pruning for the shape. This is easily done in the winter after the leaves have fallen, or early spring before flowering begins.
With your gloves on and pruner in hand, simply cut on a diagonal the vines that are leggy or not following the pattern you desire. The vines are rarely too thick to cut with normal anvil pruners. The more you cut the vines back, the bushier they will grow the following spring. Be sure to remove any dead vines or stems.

As Ted says, I cut mine down hard each year now and it grows back really strongly. At this time of year they look quite straggely so I get rid, simple really, they are quite hard to kill off! Then they soon reward you with their beautiful flowers in the summer.