First of all make sure that you have set up the ad networks that you want to work with on the developer console as described here. Then try adding the Kii ad layout to your screen layout like this:
// get scaledDensity
Display display = getWindowManager().getDefaultDisplay();
DisplayMetrics metrics = new DisplayMetrics();
display.getMetrics(metrics);
float scaledDensity = metrics.scaledDensity;
// set targeting parameter
KiiAdNetTargeting.setGender(KiiAdNetTargeting.Gender.FEMALE);
KiiAdNetTargeting.setKeywords("Application");
KiiAdNetTargeting.setAge(35);
KiiAdNetTargeting.setPostalCode("30900");
// create an KiiAdnetLayout
KiiAdNetLayout adLayout = new KiiAdNetLayout(this, APP_ID, APP_KEY, KiiAdNetLayout.SiteID.US);
layout.addView(adLayout);
adLayout.setMaxWidth((int)(scaledDensity * 320));
adLayout.setMaxHeight((int)(scaledDensity * 52));
where "layout" is your top level Android layout where you want to embed the ad box. And of course the targeting parameters are just examples on how you can limit the audience.
By adding this Kii ad box you're already displaying all the ad networks that you configured on the developer console at the same time according to the percentages of display time that you defined for each.
*Important: you need to replace APP_ID and APP_KEY with your real app values*