Walnuts are very strongly-growing trees that need a lot of space. They are not suitable for a small or medium sized garden
Broadview is a variety that starts cropping quite early in its life. The tree will do its own thing and should be left to it. No pruning is required. Just make sure the tree has a clear trunk of about 1.5 metres. Cropping will start by year 6.
Broadview is self-fertile and therefore no pollinator is needed. Squirrels can be a real problem. Do not go on holiday when the nuts are ready to harvest!