I've been using one of these on my NG furnace and crawfish burner. It works a little better for me than lighting a piece of paper or rag. https://www.amazon.com/dp/B000EDUUNK
I use a propane weed burner like this one: https://www.amazon.ca/Charcoal-Starter-Remover-Ergonomic-Roofing/dp/B0B6BVX5CF