First of all, you need to buy straps for attaching the spurs with boots and without straps, you will not be able to attach spurs with boots.
For attaching spurs to the boots, you will require chains or straps along with metal spurs which keep these spurs stick to the boots in a firm way.
You can easily find straps in the market and make sure you bring your spurs with you in order to buy appropriate and right-sized straps that are designed according to your spurs.
Before attaching the spurs with boots, you need to make sure that the U-shape of the spurs is perfectly fit for the size of your boots. The proper attachment will be possible when the spur rests at the top of heel where the boots’ body meets the spur.
Different models of spurs have a slightly different method of attaching with boots. However, usually the straps of the spurs connect at ankles and keep spurs in the proper place by coming around the front side of the boot.
There are also some models of spurs in which the chains or straps come from the bottom side of the boots and are connected near the heel area. However, it all depends on the model or style of the spurs that you have.
After attaching the spurs to your boots, you have to make sure that they rest in the same position where you have attached them.
Before riding on the horse, make sure you have done proper adjustment if the spurs of your boots are wobbling or slipping. It will help you to avoid any sort of trouble while riding the horse.