I've bought a hunter breastplate and I know how to fit it except from the bit that attaches to thre girth. How much space should there be?

I meant the strap that attaches to the girth. It's not on the bit
It should be at least an inch away from the chest and why is it attached to the bit?
Why is it attach to the bit? Breastplate does not attach to the bit.
Join the fun and sign up to connect with our 200,000 members!