This is a very good video demonstration of how to restring a traverse rod.
The rod he is working with is called a two-way stack or center draw. A one-way stack rod draws everything off to one side and only has one carrier – the one where you tie the knots.
When you are restringing your drapery rod, if you notice some of the slides are broken or missing, on the back side of the end of the rod there will be an opening where you can remove old slides and add any new ones you might need.
This opening is usually covered by a spring loaded or pivoting door that keeps the slides from coming out when the rod is in use.
I like to add one more slide than I need for the drapery or curtain that is being installed. This helps to insure smoother operation of the rod.
The slide next to the access door can get caught in the door and hang up resulting in rough operation. One extra slide is all it takes to block the access door so that won’t happen.