Someone please explain how to use this card. Do they bypass shields and do damage to hull then strip a shield or does it do damage as normal then take an extra shield.

Card does the following:

1. Spend your target lock and discard the card to perform a 4 die attack at R2-3. Nothing special about the attack steps; resolve damage as normal.
2. If the attack hit the opponent, and the opponent still has at least one shield token after damage is dealt, remove one extra shield token.

You roll to hit as normal, you adjudicate the damage as normal, and at the end if the defender still has a shield token or two, you strip one of those away as well. It's specifically designed for those heavily shielded ships.

If you hit the fore section of a corvette, could you remove a shield token from the rear?

If you hit the fore section of a corvette, could you remove a shield token from the rear?

I would say no. The Assault Missile ruling indicates that when attacking a huge ship, "defender" should be read as "targeted section," not "targeted ship." Otherwise, there's nothing stopping you from hitting the fore with an Ion Cannon or Advanced Homing Missiles and applying the damage to the aft.