Below we have a pair of Keepons Ultimate in Black. Along with the case and a piece of nylon thread. 

Close up. One piece of the pair is on the eyeglass temple. The other piece is lying in the foreground. Each piece has two parts. The main chassis with tine and separately the spacer ring. 

Your Keepons Ultimate order will arrive with the spacer ring threaded over the tine of the main chassis and ready to use. In future though, if you so happen to remove the spacer ring, for example to wash all the parts individually, then this is how you thread the spacer ring back onto the chassis tine. 

Insert one end of the nylon cord through the tine hole. 

Continue inserting until the nylon cord is halfway through. 

Bring the two ends of the cord together and insert the ends into the spacer ring. 

Slide the ring along the two ends of the nylon cord.

Continue sliding the spacer ring onto the tine. You may need to use a little bit more force here. 

Now you can insert your glasses temple through the tine hole. 

Make sure you insert your eyeglass temple in the tine hole such that the spacer ring is trapped in place and won't fall off.

Be careful not to insert your temple as shown below or else the spacer ring will slide off. 

Once your temple is properly inserted, move the spacer ring so the tine hole is tight around your temple like this:

The End.