Video demo of adding oil to your glass candle reservoir.
My favorite brand of liquid paraffin is Firefly Fuels because it is not a petroleum product, but natural gas. To see a video demonstrating the combustible value (Not flammable, meaning that it takes a wick to burn), view the video here.
Liquid paraffin is available online. Here are some options*:
Lamplight Farms Ultra Pure Clean Burn Lamp Oil
Liquid Paraffin - Pure & Clean Burning
* I do not endorse these brands. I am providing links for convenience only.