A scant 1/4" is 2-3 threads narrower than a 1/4" seam. You will literally look at the edge of the fabric where your 1/4" in seam would be, and count 2-3 threads over to the right on the fabric and that is where you seam should be :D:D:D
All of the templates I have downloaded from there, have already had the seam allowances added in :D:D:D and yes, I too have to use a scant 1/4" to get correct sized blocks :wink: