Backs sub out onr the right side end of the pool.
Forwards sub out on the left side end of the pool.

As you swim back to sub out hold your free hand out to show the subs what position you are in,

Use these 3 hand signals:
If your position is from the far side of the pool, you use an open palm showing all 5 fingers.(many fingers indicate far away)
If your position is in the center, you  showing the V sign with 2 fingers.(not so many fingers indicate not so far away)
If your position is from the near side of the pool, you use a closed fist (no fingers indicate close).