Hi, welcome to GoY, this is a shrub that wants to grow to about 25' high, with a spread of about 40', so not really a shrub for a small garden, it's pruning group 1, which 'usually' means minimal pruning, however if absolutely necessary, you can take out completely any dead, diseased, or crossing branches, and shorten any that spoil the symmetry of the shrub, and it should be ok.
The word shrub, to most people, usually means a plant between 4 and 10' tall, with a similar spread, but most plants are bought quite small, and the label doesn't always say how large the plant will get, so they're bought and planted in the wrong places, and cause problems when they start to shoot up, Derek.