I used the Bolts and nuts to secure the arms to a short section of metal sections.
I then mounted the two curved arms onto sections of a no name erector set miniset that was also sold at the store: The arms had a hole at the base so they fit easily onto the bolts that were part of the set. The first pic shows the bows I took apart.
I removed and saved the bowstrings and took both of the toys apart: Since they were both about a dollar each, the parts were cheap and relatively sturdy. BOTH of these toy bows work by using a length of elastic as the 'Bowstring'.