To get ads to display properly here is where you need to put the "ad unit links" throughout Admob > Mopub > Ludei
AdMob
1. Click Monetize new app
2. Copy "Ad unit ID" from the setting page (Ad unit ID, Automatic refresh, Text ad style, Ad unit name)
MoPub
Part 1:
1. Network > Admob, Click blue link on top right Edit Network
2. Under Set Up Your Inventory, click Edit Section
3. Under "Publisher ID" Paste Admob Ad Unit ID from steps above.
Part 2:
1. Click Inventory tab, then below graph click on Ad Units tab, click on Ad Unit link
2. Top right, click Code Integration
3. Copy the Ad unit ID from field: "Your ad Unit ID"
Ludei
1. In DevPortal go to Services > Ads (you have to have permission to have this link otherwise you won't see it).
2. In Banner AdUnit field insert Ad Unit ID from MoPub and check box for AdMob