There is 100 ways to do this, this is mine.

Go to art store and buy tracing paper "Vellum" and 3M "artist" adhesive and dust mask.

Vellum is tough and you can draw and sand and saw it and it holds up better than thin paper
3M "Artist" adhesive is thinner than the 3M 77 glue and peels off easier.

Trace out your part, cut out 1/2 inch bigger in size.

Take outside, place tracing upside down on news paper and spray. Getting spay glue in lungs is really bad so use dust mask at least!
Take tracing off news paper when it gets sticky and then stick it to your wood.
Cut out wood part, peel off tracing when done. If using 3M 77 the wood will have some sticky residue on it.