Hi Deb, are you confident the part is for 3GS? The 3GS has a black plastic piece between the metal contacts. You may have to look at some pictures to compare. If this is confirmed and the connector just won't snap into place, you need to make sure there is nothing on either connector that is in the way. Once you have the connector aligned to the one on the board, you press down. One side may go down easier than the other - press with a little force. If this does not work, don't keep forcing it - you can damage the fpc connector on the board. Patience, a couple deep breaths, and a steady hand - you will get it! I hope this helps!