How do you sew bead-work and sequins on a wedding dress?

This is one of the more common ways, but it's certianly not the only way to sew a sequin.

You need thread, a sequin, a bead that is smaller than the sequin and larger than the hole in that sequin. a needle thin enough to fit through the hole in your sequins. the fabric you are attaching it to.

hold your sequin flat against your fabric using your thumb and forefinger (or pointer). The thumb should be on the top of the fabric with the sequin and the forefinger underneath the fabric pinching everything together.

bring your threaded needle up through the back of your fabric. Preferably through the hole in the sequin. If you miss your sequin, before the needle is all the way through the fabric, thread the sequin onto the needle.

Pull all thread up so that sequin is flat against fabric and sewing thread is all on the front side of the sequin.

Thread the bead onto the thread.

Put your needle back down through the hole in the sequin (the way you came out) and out the back of the fabric.

The bead will be holding the sequin to the fabric. You can also make a small stitch through the back of the fabric to 'stay' the sequin after this step, but if you are moving on to add more beads and sequins it's not totally nessisary.