Hi Tony
As Alan sys the pump is probably an optional extra and may not be fitted on all engines.
If you do not have it, but intend to keep the boat getting one and fitting it will make the job much easier, now and for future oil changes..
However if you have another type of pump it can be simply connected to the tube mentioned by Alan, making sure you have a good tight connection.
To make the job much easier run the engine until at running temp, then shut it down and pump the hot oil out. [it is then thinner] be careful its hot.
after empting sump, change the filters.
If you are going to do the job yourself. Dan has just done a writen project all about this for the Marine Skills center.
Its long and in depth but I am sure he would not mind me emailing you a copy to read before you start.
Of course if you have any doubts or need more help just call.
Charlie