Reddit mentions of 1 can of Newport 300ml Ultra Purified Butane Fuel Zero Impurities

Here's the link

Also, I dont know how finicky these are with types of butane. A guy on r/cigars mentioned that he had been smoking cigars for 25 years and had tried all sorts of butane. He uses Newport Butane It's cheaper to buy this stuff 2-4 cans at a time. Usually the more you order (at least on amazon) the better the deal. Pure butane wont clog the lighter like some cheaper butane can.

And please search youtube for how to properly fill and un-fill butane lighters.

Lastly a tip I found on the packaging before throwing it away: Do not press the ignition switch hard and fast, just gradually push it. I was having to press the button 1-2 times to get it to start but since Ive started pressing it softer, it lights on the first shot each time. The best way I can think to explain it is to press it as if you were really tired and relaxed. You'll hear the gas release about 1/8 of a second little before the button clicks.

Also the flame is adjustable. The pic shows a medium flame.

You just need to use a fuel adapter. It uses an old style needle valve.

Newport Gas (as well as several other butanes) come with a bunch of little plastic adapters in the cap:

https://www.amazon.com/Newport-300ml-Purified-Butane-Impurities/dp/B00GMPCBHC

The red adapter will let you fill the lighter.