what you'll need:
next cut out your design, this can be pretty tedious depending on your design. sadly the sun went down while i was cutting so all my good lighting went out the window...ah working in the dark because i'm too lazy to turn the light on... if you have a lot of fine lines in your design i'd recommend making them a little bit thicker than you think you need to.
now, place the parchment paper inside your shirt directly underneath where you'll be placing your stencil. line your stencil up on top of your shirt, shiny side down. using a press/lift/press motion (not a sliding motion) iron your stencil to your shirt. make sure you get a good seal otherwise your paint will leak. if you have any separate pieces or free floating pieces iron them last.
double check you didn't miss any spots with the paint, and once it's dry you can peel off your stencil.
and your shirt is ready to wear!!