Making flames:
Toribash > Setup > Utils > Flame Forge
You will get a menu of different options on how to create a flame.
After you create it you get the option of naming the flame then click "create" to make it.
Once you make a flame it will automaticly become an item in your inventory.
However I personally reccomend buying on the flame particle sub-forum or the market. You will find flame WAY cheapre then it costs to forge a custom one.