With cold-damaged shrubs and trees you have two choices. You can either prune out the dead portions now or you can simply wait for new growth to emerge and then cut back to just beyond the new growth.

If you wait, the presence of new growth will eventually make it easy to tell how far the plant has died back and thus where to prune.

If you wish to go ahead and prune now, you can first determine where the plant is alive and where it is dead. This is easy to do by scratching the bark of a branch (starting at the tip) with a knife or the blade of your pruning shears to expose the layer of tissue just underneath, the cambium layer. Where this layer is green the wood is alive. Where it is brown or black the wood is dead. The dead wood can then be pruned out.

Whether you prune now or wait for new growth, be patient. It may take a few weeks of warm temperatures before much new growth emerges.