However you choose to store your sectional dock system, it is recommended that you store the sections from last (on the ground) to first (on top).  This will allow you to assemble the sections in order without having to rearrange the sections to be able to place them in order and it will also keep the dock from being assembled in the wrong order.
For faster installation in the Spring, you may choose to leave the legs and bracing extended.  If you choose to store your sectional dock this way, make sure to place the L sections in a separate stack from the straight sections.  Also, make sure the frames are resting on the bracing of the previously removed section and not on the dished footpads.  Resting the frames on the dished footpads may damage the footpads causing them to have less suction and less stability with waves, winds, and storms.
For a neater shoreline appearance (or if you have limited space) the bracing may be folded down creating a lower profile and a more compact storage.  If you choose this method for storage, you will want to fold the bracing as you remove the sections.  You may also want to have another person help you to stack the dock sections.  This will help to reduce injury to yourself and damage to your sectional dock system.