Instructions
Open the main menu system at any point during a game. Select the schematics for the armor you want to build from your "Items" inventory page, which lists all of the equipment you need to create that particular class of armor. Write down this information on a piece of paper for easy reference or refer back to the schematic at any time.
Travel the Capital Wasteland until you find all of the equipment you need to build your armor. Find spare equipment throughout the Capital Wasteland. Check any dead bodies, dead monsters or abandoned buildings that you come across. You can buy certain pieces of equipment from supply shops in towns.
Go to a work bench. Workbenches are the areas in the game where you can modify and create new equipment. Most shops, such as the ones in Rivet City and Megaton, have work benches. Your home in Megaton, if you've unlocked it, also has a work bench.
Stand in front of the work bench and activate it with the "Interaction" button listed on screen. For example, on a PlayStation 3 console, select it by pressing the X button. Select each of the required equipment from the window on screen individually. Select "Combine" to create new armor using old supplies.