Use the metal spudger to dislodge the two clips on each side of the arm.

The two clips are at the front and back sides of the arm.

Remove the arm but pulling apart the two sides of the arm away from the casing and lifting the arm free from the casing.

All 4 clips must be dislodged in order to free the arm. Be careful not to accidentally reconnect one or more as you dislodge the others.

Removing the arm takes moderate force. The plastic is strong and should not break, but be careful with yourself and your X10.