It's pretty simple, just reload the save (chapter 29).
At this point in the game you should have enough fuel to get 3-4 boosts.
I would recommend doing this once you've completed the game as you will burn the majority of your fuel and will struggle for the rest of the journey.
Fill up the fuel, keep the line on the bottom deck full, while pumping air to get the pressure into the blue. Keep dousing the engine to keep it cool and once the blue button for the boost module pops out, push it to start the boost.
While you are boosting, fill the fuel from the line and prepare to rinse and repeat. It really is very easy and I was surprised how quickly I got it.