How to pattern O/U shotgun?

[bucktooth7]

I hope this is the right forum for this question. I tried the "search function" and a bunch of other stuff came up but not what I want. I have a new O/U and I do pretty well with it shooting skeet but my trap shooting has gone down hill. I usually use a modified choke for trap. My club has a pattern board. Tell me the best way to go about this.

Ed

[Fjold]

http://www.wildlifedepartment.com/shotgunpatterning.htm

http://www.gunnersden.com/index.htm.shotgun-patterning.html