fittings 26 the body 48 of each jack 46 is slid down over the foot base plate extension 50 fig1 a the bolt head 52 of the jack is pushed through a keyhole 54 on the corner vertical rail 24 and the jack is slid down to lock it in place the jack 46 is then rotated towards the rail 24 and twist lock 56 is inserted into the hole in corner fitting 26 and twisted 90 degrees to lock fig1 b and pin 57 inserted to lock the foot baseplate 58 is then dropped to the ground and pin 59 inserted to lock the extension 50 referring to fig1 handles 60 are inserted into sockets of the jacks 46 and the handles are cranked to level the container cranking two jacks at a time prior to lowering sides 12 intermediate supports 62 are installed on the lower rails 20 at the locations 64 shown in fig5 to permit large loads to be supported in the shelter the foot 63 of support 62 is threaded so that it can be extended by rotation of nut 65 cribbing 66 is used where the corner posts are more than 3 inches above grade the sides 12 are then lowered as shown in fig7 and 8 and using a winch as described in u s pat no 5 761 854 the winch.