Enabling the Ads Service

Initialize the SDK early in the game’s run-time life cycle, preferably at launch, using the Initialize function. For example, if you want to use Google Admob platform, that is how you init the ads client. 

using SA.CrossPlatform.Advertisement;

UM_iAdsClient client = UM_AdvertisementService.GetClient(UM_AdPlatform.Google);
client.Initialize((result) => {
    if (result.IsSucceeded) {
        Debug.Log("Advertesment platfrom is ready to be used.");
    } else {
        Debug.Log("Failed to init " +  result.Error.FullMessage);

As you may notice, we haven't provided any setting. Settings required for the client to function properly can be provided via Plugin UI using the 3rd-Party Tab. Or via Code. How to provide settings via code will be described for every platform explicitly.  For example, check the Google Admob configuration sample.