Putting the boat on the side is best done on grass in my experience.
Pull on the trapeze as Karl says and catch the shroud. Then walk the mast down. Have a chair or table ready to put under the tip of the mast.
To right the boat again, reverse the process and make sure you use the trapeze to get good leverage as the topside hull is headed for the ground. Stay too close to the boat and you will not have enough leverage to stop the hull from crashing down.