Probably most of the freezer paper that is sold is used by quilters for templates. It has the great quality that you can iron it shiny side down on a piece of fabric and it sticks. You can even pull it off and iron it onto another piece of fabric. I just wish they'd make it in wider rolls. The alternative is to butt two pieces together and join them on the dull side with drafting tape.
However, for the Hellebore quilt, I could treat each square as a separate element and so only needed small squares of freezer paper. I taped one of the drawings onto my light box, then taped the freezer paper on top, with the shiny side up. Why the shiny side? Well, this goes onto the wrong side of the fabric and that results in the finished, right side up piece being exactly like the drawing. If you made the templates with the shiny side down on the drawing, you'd end creating a mirror image of the drawing and, believe me, this would be much harder to work on.
Using an ultra-fine black Sharpie, I carefully traced over the lines and the outline of the square.
Then, turned the freezer paper the right side up and put it alongside the drawing. Next, in pencil, I transferred the numbers from the drawing to the dull side of the freezer paper. This is a bit tricky since the dull side is a mirror image, but it works. I also used a highlighter to outline the edges of the square. This helps you to use the straight grain of the fabric for the edge of the square, where possible. In another highlighter color I usually mark the major section lines. Not essential, but it helps when you are putting the jig saw puzzle of fabric together.

This is a picture of the freezer paper template, dull side up, for one of the leaves. I used straight edge piecing for the leaves.
Note the colored tick marks crossing the lines. I used a different color for each side of a given element - look at D1 - green ticks on the boundary with E1, black on the border with C1 and orange on the other side of th triangle.
"Tick marks are your friends!" If you skip this step, you will learn why we say that. They are what tells you which side connects to which other piece - once these elements are cut apart it is amzingly difficult to figure that out if you don't have the tick marks. I pinned this up to just to take the picture - normally, it will be pinned shiny side up on top of the copy of the master drawing on the design wall.