Lots of good advice above. But if I were you, if you have no experience of DLs, try it first with the ship stopped, with no pitch or roll (ideally, at anchor). Get used to the size of the deck, and where your hover references are before you think about doing them under way. Also, double (and triple) check all the tie-downs are off before you try to take off, and make sure the deck is clear of FOD and random sight-see-ers before you try to land.