Further to my previous reply…
On further study of your photo, it could be as follows: Thread a 2mm
silver bead onto fine beading thread or wire and centre it Double the
wire and thread both ends through the pendant bead(s) Take one end of
the wire and thread one side of your necklace Take the other end and
thread the other side of your necklace.
Finish both ends with a clasp however you like.
I don’t bead, so I’m kind of making this up as I go along - others
may have a better idea!