Simple break up your digestives into smaller pieces (but not too much otherwise theres no crunch, just enough so they fit in one half of the piece of bread)
Step 3:
Fold the bread over the chocolate digestives + enjoy
Step 4:
Step 5:
Obviously works just as well with 2 slices of bread + that way you can fit more biscuits in, but i prefer the folding method as im cheap + this way saves bread.