Step 1: Cut the Stencil
silk screen (silk screens usually have rectangular frame made out of wood or metal, with silk fabric stretched across the frame)
something to make a stencil
I would recommend:
acetate paper (clear paper, basically the same as what you would use to write on on an overhead projector)
contact paper (you can buy this at ACE hardware, it can be colored or cloudy/transparent and it is sticky on one side)
screen printing ink (silk screen ink)
The easiest and cheapest screen printing method uses stencils to make the print. To make these stencils, place a sheet of acetate over the sketch and traced over the lines with a sharpie. I find that acetate is easier to use than contact paper because it is transparent, can be easily cleaned, and can also be used as a stencil for spray paint.
Step 2: Tape the Stencil to the Screen
Make sure that when you place the stencil that the image facing you is the mirror image of what you want to be printed; if you are printing words, the words should appear backwards when you put the stencil on the screen.
Next tape down the stencil. I use masking tape, because it is more water resistant than scotch tape but still peels off of the screen without damaging it. Also cover all of the other areas of the exposed screen. All of the negative space, or open areas of the screen will allow ink to be pushed through. I usually use spare rectangles of contact paper, or folded newspaper to cover the open areas of the screen.
Step 3: Print
After the stencil and screen are lined up, place a line of ink at the top of your stencil and spread it around, making sure to cover the majority of your stencil (I find that spoons work very well for this). Next use the squeegy to evenly spread the ink over the whole deign (taking care to make sure that all the parts of the screen that are not blocked by the stencil are covered with ink). This is called flooding the screen, which ensures that there is ink in all of the open areas of the stencil. Do this by placing one, or both hands on the squeegy and pulling toward your body at about a 45 degree angle. Make sure that when you are doing this, the screen remains stationary (you can do this by either having a friend hold the screen in place, or working on the ground and placing your knees on the frame of the screen to keep it steady).
Once the screen is flooded (there will be excess ink at the base of the screen) repeat the same motion with the squeegy while applying more pressure. This should make a scrapping sound, similar to the sound your finger nail would make if you scratched the screen. Repeat this 2 or 3 times to make sure that the ink has been pushed through the screen onto the material below.
I would recommend practicing this technique first to get a better idea of how much ink is needed to flood the screen and how much pressure is needed to push the ink through the screen.
Next, lift off the screen from the material that was printed on (keep in mind that the material, especially if it is fabric, may stick a little to the screen). Wash off the screen while you let the ink dry. It is important to wash of the screen as soon as possible so that the ink does not dry in the screen (dry ink will block future ink from being pushed through the screen, and will therefore change the design).
Once the first layer is dry you can print on top of the first layer with a different color using the same process if you would like a multicolored print.