Oh dear god, did you buy MTR grip?!?
If you did, sell the grip, or return it to the vendor if you can (distance selling rules n'all that).
As per the other thread, you will not find any kind of happiness with that grip. The angle is wrong. The receiver/grip interface geometry is wrong. It's a spare part for a certain type of ICS M4. It doesn't even work with other ICS guns. I'm not saying it's completely impossible to make it fit, but you will need to be pretty inventive with a Dremel to stand a chance of getting it to work.