What tools are needed to hammer the support?
Sledgehammer (or something similar), wooden (metal) spacer, level.
To what depth is the fence pile installed?
It all depends on what material the fence will be made of (from a mesh "chain-link" or from 3D panels), as well as the height of the fence and what kind of soil will be used to install the fence.
Suppose you have clay soil on your site, then to install a fence made of a chain-link mesh, you will only need a hammer-in support 600 mm long, when installing a fence made of 3D panels, I suggest using a hammer-in support with a length of 850 mm. A hammer-in support 1500 mm can be used under the foundation when installing the wicket.