It needs to be transplanted to a wider spot. These containers are pretty much temporary so they have more space to grow. If they are broken, you can cut the flower but not the stems. This plant grows from new and old wood so if you cut now you won't have blooms.
Since the plant is not stablished yet, I would not touch it for now :) if you cut the branches and stems there is a change you won't have blooms since this flower grows on new and old wood. Honestly, no need to touch the first year :) just dead leaves is needed.