Drain Cover onto a Pipe, and the Drain Cover needs to point at a River or similar infinite Water Source. (Water enters from the sides or from above the Drain)
If you decide to use the Ocean, you need to use a Dryer to turn the Ocean Water into Distilled Water. It is also generally better to use Distilled Water instead of regular Water.
Everything involved has an automatic Fluid Output so you do not need any Pumps to get the Water from your Source to the Dryer and from the Dryer to the Boiler.