Hi,

This is largely a question of what type of shrub rose you have and how tall you want them to grow. Shrub roses are very vigorous and will recover from your pruning.

Healthy canes are green. Prune those back to an outward-facing bud to ensure that branching grows out rather than to the interior of the plant. Cut out any brown canes or brown ends of canes; those are dead.

This web page is from Nebraska and has good tips:

https://lancaster.unl.edu/spring-rose-pruning

I hope this helps.