my leaders came with velcro strips, do a chalk line across your bar and then sort of blow excess chalk off before attaching the velcro to the poles
If you don't get them on straight your quilts won't be straight and the velcro will eventually move even more crooked as your always pulling on it. Thats what I did. does your poles have a heavy pold or poles that you put together, if so the middle line on your poles is your middle and thats where you put your middle of your leader. If you have the heavy solid poles I don't know how those are attached.