I'm no expert on roses; hell I only pruned my first roses last year and I got two blooming sessions that season ^^ What I know regaring pruning roses is: first cut all that's dead, diseased/dying and crossing. Then, in you mind's eye visualize how you want the rose bush to look like (which branches to keep) and cut back to an outwards facing bud to about knee height.
My result first try:
Pruned again last week keeping just a few stems:
