Preparing a Finnish gap fire is fair easy to do if you have a supply of wood available. Pine is typically your best option to to get a quick, long lasting fire going, but Birch can also be used for this task as well.
If you are looking for a better way to keep warm when the weather is cold outside, then this Finnish Gap A fire is the answer. Suggest you might want to try it at Homestead before using during a night in the wild.
On the next page are great instructions for building a Finnish Gap Fire.