You should read some more, good sir! A very common practice, mentioned in many builds and tutorials, is to use a ruler, and go over all of the fold lines with a ballpoint pen. Of you press down moderately hard with the pen, it will indent the paper and make it very easy to make clean folds along the lines.
As for the triangles you mention, someone else will have to chime in, as I'm not familiar with the model you are using. Remember that you sometimes have to get creative with certain details, though, and sometimes try methods that others haven't used before!