How can I connect this controller to iPhone/iPad? [djay for iOS]

Depending on the models of iPhone/iPad you use with DDJ-WeGO3, the cable needed to be connected are different.

-For iPad Air, iPad mini with Retina display, iPad (4th generation), iPad mini, iPhone 5s, iPhone 5c, iPhone 5, iPod touch (5th generation):

　Connection cable for iPhone/iPad (Lightning) included in the box of DDJ-WeGO3

-For iPad (3rd generation), iPad2, iPhone 4s:

　Connection cable for iPhone/iPad (30-pin Dock connector): DJC-WeCAi30 sold separately by Pioneer

Be sure to use the cable compatible with your iPhone/iPad model in advance. Then, follow the instruction described in the DDJ-WeGO3 Operating Instructions (DJ Unit Setup).