Wash your screen in the sink with warm water, dish washing liquid and a scrub brush. Lay out all your supplies from your kit.
Design your artwork on the computer and print it out on 8.5-by-11-inch paper. Your design should be simple and one solid color. Tape your paper, using painter's tape, to the back of the screen, facing the design toward you.
Trace your design with a pencil onto the screen. Remove your paper from the screen, and turn the screen over. A reverse of your image now faces up.
Paint the design with the drawing fluid, using a small paint brush on the same side as your tracing. Allow the fluid to dry thoroughly. This creates your image.
Tape the edges of the screen with painters tape to prevent the filler from seeping. Squeeze a thick line of screen filler across the top edge of the screen, and drag the filler down the screen with a squeegee. Scoop any excess filler out of the screen and place it back into the bottle. Let the screen dry for at least 24 hours. Wash your squeegee with dish soap and warm water.
Place the screen in a sink, and run cold water on the screen to remove the drawing fluid. This exposes the image portion of the screen. Allow the screen to dry.
Tape the edges of the screen with painters tape to cover any openings at the edges of the screen. This prevents the ink from bleeding out the edges.
Place a piece of cardboard inside the sweatshirt, to protect the ink from seeping through. Position the screen over the sweatshirt, laying it out where you want the design to be.
Squeeze a thick line of ink across the top of the screen, and drag the ink down the screen with the squeegee. Repeat this step three or four times, then carefully remove the screen from the sweatshirt. Allow the ink to dry thoroughly.
Rinse your screen and squeegee and allow them to dry.
You'll need a variety of screens. First you'll need to figure out what frame size will fit your press, then decide what mesh count you need. 80-110 mesh ct. is good for putting down a lot of ink, especially if you want to put down a white under base. 156-230 mesh ct. for designs with a lot of fine details and/or halftone dots. If you're going to do 4 color process, you'll need mesh counts of 305 or higher.
Next you'll need to decide on what type of ink you're going to use. Plastisol ink is the most commonly used ink for t-shirts and is the easiest to use. It is heat-set ink, so you'll need a flash unit and a dryer to properly cure the ink (sometimes a heat gun will work, but it takes longer and you may scorch the shirt).
Water-based inks are good for t-shirt printing, as well, but are harder to work with. They tend to dry out in the screens fairly quickly, so you have to be aggressive when printing. If printing on shirts, this type of ink needs to be heat set as well.
You'll need emulsion to coat your screens. The type of emulsion used will be based on the type of ink you're going to use. If you're using water-based inks, then you'll need emulsion that is formulated for that type of ink. Emulsion can come pre-mixed with diazo, which is the chemical that causes the emulsion to cross-link when exposed to light. You can also purchase emulsion and the diazo separately and mix then yourself. The emulsion is sensitive to all light, except yellow light, so you'll need some yellow light bulbs and a room where you can block out all other light. You'll also need a scoop coater to apply the emulsion to the screen. You'll need one the will fit inside the screen frame.
You'll need some type of exposure unit to expose your screens. These can be high end models with vacuum tables, or you can make one with a high wattage halogen lamp and a piece of glass place over the screen and the film (this is what I use).
You'll need a wash out area to rinse out and/or reclaim the screen. You'll need a pressure washer and a regular hose with a sprayer. You'll need some cleaning chemicals such as press wash, emulsion remover, de-greaser, ink de-gradient, and de-hazer. Some of these will be different depending on the type of ink you'll be using.
Squeegees. These are what is used to force the ink through the screen. They are measured by the hardness (durometer). 70-75 durometer are usually sufficient. Squeegees come in various sizes, so you'll need to figure out which ones will work will the frames you're using.
Tape. Wide masking tape is used to tape off the sides of the screen to prevent ink from seeping through area that don't have emulsion. Some places will try to sell you special tape made for screen printing, but masking tape works very well and is less expensive.
This is a long list, and I probably forgot some things, but for the most part these are the basic items. If you're new to screen printing, do some research before you get to far into it. Screen printing may seem easy, but it's actually somewhat difficult if you're unfamiliar with it. Trust me, you will make mistakes, but all in all, screen printing is very rewarding and fun.