Before starting, you probably want to maximize your character's carrying ability: minimize the amount of extra equipment you are carrying, and gather as many Feather or Fortify Strength potions, enchantments, or spells as possible. The procedure is:

1. Head to Frostcrag Spire,and clear out all of your stuff from the storage area. Once this is deleted, the items can not be recovered. Create a save while your character is standing in the Living Area of the tower; standing in the section of the Alchemy garden with oblivion plants (bloodgrass, harrada) has been found to be the most reliable location.
2. Delete the plugin file. To do this on Xbox 360, go to the system blade in the dashboard, open the memory menu, then delete or move the Wizard's Tower file (you will be able to download it again for free later).
3. Load up the saved game, ignoring the warning about missing content.
4. You will find yourself in the TesterBrumaHouseMid area. If your original save was in the correct spot, you can skip the following step. Otherwise you will find yourself falling and unable to easily move. You want to move yourself towards the fire that can be seen to the south.
* This step can be tricky. It has been reported that turning towards the fire, drawing a sword, and swinging while trying to move in the direction of the fire will cause you to move towards it.
5. Wait for the game to drop you outside the level (which will teleport you to the house). This house is the same as the Dark Brotherhood quest Accidents Happen.
6. Head out the door and you will find yourself looking at a circle of houses around one of the Bruma fires. Most of these houses you cannot enter, but there are 3 you can, the one you came through, and the other one labeled the same (except with a "Not Something People Want You To Go Through" red sign). The third house leads you to an unlit Sigillum Sanguis.
7. Enter the third house. Equip a Torch or cast Nighteye and make your way up to the Sigil Stone. This is the tricky part, to get the Sigil Stone, you must jump out to it and activate it, but be careful, the drop hurts. The recoil and damage from the jump can be avoided if you enter the door right before hitting the ground.
8. When you activate it, you hear the familiar sounds but no animation of activating a Sigil Stone. When it gives you the Sigil Stone, check your inventory, you'll see EVERY type of Sigil Stone available at your level (Meaning level 20+ will get all Transendents) and they will fill your inventory.
* Repeatedly entering and exiting the house will cause more and more Sigil Stones to be added to your inventory; you are only limited by your carrying capacity.
9. Cast feather spells or potions to be able to move, because you are probably over encumbered.
10. Outside, near the rock and the Bruma Fire, there is an Enchanted Mace, Mace of Doom. It only weighs 5, but carries a huge charge and a devastating fire spell.

See Exterior Test Cells for more information on what can be found in this test world. When you are finished here, fast travel to anywhere.

Once you are finished, re-download the plugin and put all your stuff back. Note that if you load a savegame where you had items stored in the tower before re-downloading the plugin the items in the tower will be removed from that savegame forever if you then save over it.