If you haven’t pruned yet, panic not.
Just gather sharp secateurs, pruning saw, some gauntlets and a reckless attitude. If you're unsure, then it pays to be bold rather than tentative; roses really are the big bruisers of the garden and can take a proper beating, so don't be shy.
It's okay to get it wrong! You may lose some flowers, or your bush may be wonky for a bit, but who cares? It'll right itself at some point down the line, and YOU'RE LEARNING
Rush out and chop dead, diseased or dying wood, and anything spindly right down to the base on all your roses, after which, a shrub rose (a bush) simply needs all stems pruned by one third of their height. Try to cut just above a bud, but don't sweat it; your aim should be to get the thing tidy. For climbing roses, remove anything that's not going to play ball when you try to tie it into your framework, so if it's sticking out or too tough to bend to your whims, then chop it. For ramblers (climbing roses that flower only once) then take out a third of the oldest shoots. Hybrid teas (big flowers on single stems), and really overgrown monsters need razing to about 10cm above ground. Treat floribundas (many flowers on single stems) the same way, cutting higher up though, about 30cm above ground.
Finally, give them a feed after pruning with rose fertiliser. They also love a good helping of manure around their roots.
There you go. Now just do it.