Vienna Reins and Draw reins both slide through the snaffle rings of the bit, but Vienna reins are fixed at two different points, whereas draw reins are fixed at the girth, but held in the riders hands.
Here’s 2 pictures of Vienna reins, set up for both riding and lungeing (which is the only way I have used them - adjusted pretty loosely)
Vs draw reins, shown here with a rider who also has the option of using a plain snaffle rein with this set up