There is no oxygen besides helium and hydrogen on Neptune, so you may need a lot of Oxygen supply. You may also need lots of food and something to keep you warm as there is no possible life and Neptune is also completely covered in Acid waters.
There is no possible way to live on Neptune because it is not a solid planet. All planets beyond mars are made of gasses. furthermore Neptune is at to great of a distance from the sun. on a hot day it is -425.
A place to stand, to start with.the planet is a gas giant. There is a small solid core, but you would be crushed to death by atmospheric pressure long Before you reached it.No life form that we are aware of could live there