The case slides open to reveal a clever mechanism. Simply insert the needle with the eye facing open to the threader pin, push down on the lever to test. If you feel resistance, Stop, the needle is not correctly aligned. Realign needle and retest. Once correctly aligned, lay the thread into the “V” groove. Then press the lever to guide the threader pin and thread through the needle eye. Remove the now threaded needle. Use with a gentle touch, do not force. We recommend you view the demonstration video to ensure correct use.