First, supplies you need. the art work
a piece of matt board (acid free is best)
same size piece of foam core (1/8" or 1/4")
matt knife (box cutter)
ruler (straight edge...with a metal edge)
framers tape (masking tape will yellow and damage art work over time)
matt cutter (if you want beautiful 45 deg bevels)
First, determine the size you want your finished matted piece to be. Usually I'll allow for 3" sides on my cut mat, so measure the "window" you want surrounding your art and add 3"
Set the cutting edge of your matt cutter to 3"
Slide your already cut to size mattboard into the cutter face down. Use the straight edge of the cutter to draw a pencil line on each side. This will give you the start and stop point for the bevel cutter.
Here's how an intersection will look
Clip the bevel cutter onto the slide rail and depress the thumb lever that controls the blade, slide the unit across the matt board and release the blade when you reach your pencil line
Stopping and starting at each pencil line, cut all 4 sides
Pop out the center piece you've cut and you should have a beveled window that will surround your art
Next, hinge the mattboard to the foam core. Butt the 2 pieces with both pieces right side down and tape along the TOP of the assembly with framer's tape (could be the short dimension or long depending on the orientation of your work) The one I'm showing happens to be a vertical piece
Next, lay your artwork on the foamboard and center within the window of the cut matt
Use a small piece of framer's tape and attach the art work to the foamboard
Artwork should be securely held and beautifully framed within mattboard
And, after framing, here's what it looks like
oops, different piece of art, but you get the idea!
Now, if you're TOTALLY confused, please look at this video...
it is very well done and a lot easier to understand. The matt cutter is an investment, I think around $160 from Dick Blick...but if you frame alot, well worth it.