If you are taking wood from a newly cut tree, cut logs to a length that will fit in your fireplace. Split these logs and stack them in a sunny area outside, away from the foundation of your home (do not attempt to season your wood inside or near your home). You will only be encouraging potentially damaging insects to take refuge inside your home.
Encourage air circulation around the ends of the logs by leaving the sides of the stack uncovered. You can protect the wood from excessive moisture by placing a tarp or canopy over the top of the stack.
Allow the wood to sit idle for at least six months, depending on the season. If you stack newly cut wood in the spring, it may be ready to burn within six months. If you stack your new wood in the fall, the colder winter months will necessitate a longer drying period.
Check to see if your logs are seasoned and ready for use by looking for deep cracks in the ends of the wood pieces. Test the dryness of the wood by splitting one of the pieces. If it splits easily with an ax, it is likely ready for use.