Gas stations are scattered around the island but typically don’t operate 24/7. They all accept both US dollars and NAF. Many do not take credit cards. Some do. You need to pay first, and they will tell you which pump to go to.
The yellow handles are for ‘gasoline/petrol’ and the black ones are for ‘diesel.’ If you don’t use as much as you gave them, just go back, say your pump number, and they will refund you.
Note: All gas stations on the island have the same price.