1. Strip some solid core wire.

I am using 32AWG but 36AWG would probably fit a bit better. Leave about 1inch/15mm of excess wire. Try to make the joints as flat as you can

2. Align the original crystal and solder to the edges.

Add flux and hold the iron for a few seconds to make sure it has a nice strong joint to the side and the bottom pads

3. Once completed, gently lift the crystal to make sure you have good contact.