I inevitability the land bridge construction machinery for quay construction on the island?
A jetty normally have a piled foundation, so assuming that you have a suitable seabed.
Some form of piledriver or water / nouns jetting device to install the piles. This will depend on their loading requirements.
A crane to assist with the decking. For a simple ramp you may be able to use manpower.
Some more information about the size of the quay and its future use would be useful for a more complete answer