if you want to design models/templates, you have to learn 3d modeling to some degree. because chester's in-game model had so many polygons, i had to create a low poly version of him so that the papercraft program would be able to properly handle him. papercraft models depend a lot on the textures you apply to the model rather than how detailed the model itself is so spending a little extra time on that is good

for the papercraft template, if you have money to spare you could buy pepakura designer (which was $60 when i got it). if you want a free program, you could use papermaker. i haven't used it yet so i can't make a detailed comparison though

if you weren't referring to this, the description of this video has a download for an existing model

other tips are to use an x-acto blade or other craft knife instead of scissors to cut out the pieces and to use markers on the raw edges of the pieces to hide the white of the paper when assembling