These aren't curb bits, so they don't require a curb strap, and certainly not a curb chain. ... The curb's only purpose with a snaffle is to keep the rings in place—there shouldn't be any contact made with the curb to your horse's jaw when you pull on your reins.

Do I need a chin strap with a snaffle bit?

On a snaffle, a chin strap will be very effective in keeping the bit from pulling all the way through the horse's mouth when using one rein. It need not be adjusted tight and is normally placed between the reins and bit. The one exception to the need for a chin strap is with the full cheek snaffle.

Where does a curb chain go on a snaffle bit?

Buckle the curb strap onto the bottom of the snaffle bit ring on the left side of the bit. The curb strap should lie under the horse's chin, and behind his muzzle. Adjust the buckle so you can slide two fingers between the curb strap and your horse's jaw line.