Establishing a relationship with a horse is very important. You want them to be comfortable around you and teaching them to hook on to you is a great way to gain that trust. When you first start it may take a bit, and that's ok. Don't rush the process, every horse is different. You can do this with nothing no line, no flag, no whip, just you and the horse. Eventually you can do this with whatever tool you have.
As always it takes time, patience, and practice!
Soft Hands, Soft Horse