You’ve got your hands on some green wood. How do you store it?
If your winter stays below 40 or 50 degrees, take your time, it will probably keep fresh till spring. However, with several recent warm winters, rot seems to be becoming a year round event here in the Carolina Piedmont.
If it’s summer, you could treat your wood no different, splitting out parts as needed. This is what I do. Keep the logs as large as possible to prevent drying. Sealing the ends of the log with end-grain sealant will reduce checking (apply as soon as possible after sawing the log). Or just leave the log a few inches longer than what you need. Exposed tangential surfaces can develop checks, so try to keep the bark on the log and your splits radial (from the bark to the pith). You can apply sealant to tangential surfaces too.
Rot: Sapwood is not rot-resistant in any species, so it’ll rot first. Some species are mostly heartwood, some mostly sapwood. Maple is mostly sapwood and will rot before you can sneeze. Oak heartwood gets full of powder-post beetles long before it rots. I’ve heard walnut will last one day longer than stone. Any log over 12″ diameter will rot long before it dries out (this may not be true in deathly dry parts of the world).
Roughing out parts If you’ve got the energy, you could split the whole log up and rough out your parts. Spindles can be shaped then roughed to an octagonal cross section. Backs can be bent. Turnings can be roughed to cylinders. In this state they will dry with minimal issues and keep indefinitely, but as your skills progress you may look askance at the pile of parts you made three years ago.
Wrap parts in plastic to prevent drying, and they will keep for a few weeks in the summer (longer in the winter). Watch for mold which can lead to decay.
Freezing will keep wood green indefinitely. If it’s a self-defrosting freezer, wrap the parts in plastic so they don’t dry.
Submerging wood in water will prevent decay, but the parts may eventually smell like something your dog did. This goes away after the parts are dried. I have used ponds, watering troughs, garbage cans, pipes and wheelbarrows.