The Cloud Recognition samples of the SDK release 2.8.7 (native samples version 2.8.8, Unity samples version 2.8.9) show how to start a Cloud search for target recogniton, using a sample DB.
In particular, the samples make use of the TargetFinde::start() API, by which the sample will enter a search mode where your Cloud Database is scanned for a possible target match. See also these pages for more details on Cloud Reco API usage: