You can make your own "kiln" by putting the boards in a somewhat sealed area with a dehumidifier. This will dry wood up to 10 times faster, but it will bow, curl, cup, and twist more. This is minimized with wood as thick as yours. It is vitally important that there be airflow around each board, and that moisture not be conducted through the ground, concrete, or wood exposed to moisture.
On green wood, I store it outside, under good shelter and shielded from splashing or conducted moisture. Then I put it in my shop with a dehumidifier until it acclimates to the shop. On wood like yours, you can store it outside for 4 months in late summer/ early fall and store it in a dehumidified shop for 3 to 6 months to get the wood to about 12% moisture content before milling to rough size. Another few weeks in the shop will finish it off and minimize wood movement as related to speed of drying.
Another, and expensive method is to make a special kiln room. You can mill the boards to rough size green and clamp it to box, not round, metal spacers (or even better, custom reinforced plastic spacers) to hold the boards from movement during the drying process. The metal can rust, staining the boards. Even aluminum will stain somewhat, so make sure that there is a barrier such as polyethelene strips between metal and wood. It also takes a lot of strong clamps and spacers attached to a solid base, such as an I-beam frame. Put in a dehumidifier an make sure that there is only minimal airflow to the outside air (say less than 2 sq in total). The boards will dry lickety split. To reduce movement even more, you can re-wet the wood evenly (still in clamps), let it soak in a day, and re-dry. A friend of mine has this arrangement. It is just too expensive for me.