My civilian shipping line just built a fuel refinery ship and placed it at Neptune. How do I buy fuel from that ship? I dont see a way to do it.
Use the advanced search tool at the top right to research posts, this was covered in the last couple of weeks.
To buy fuel from a civilian harvester, send a fleet or a tanker to refuel from the harvester. The cost of the fuel will be deducted from your wealth and show up as a line item on the wealth summary tab. I prefer an in-system tanker with a slow very fuel efficient engine and 5,000,000 liter fuel tank that shuttles back and forth unloading 90% of the fuel to my colony (earth) before heading out to buy again. The more fuel you buy from civilians, the more harvesters they will build. Make sure your tanker has the tanker box checked in the class design window, otherwise Aurora will filter out the tanker related orders, such as "unload 90% to colony".