In order to fetch data from a particular account, please ensure that the 10 digit AdWords account ID for that account is defined against the property
clientCustomerId in your properties file. As an example, if you use the Java client library, you would need to define the relevant account ID
here. If you prefer to use an AdWords session object (instead of properties file, as mentioned
here), you would need to update the value of the variable to the respective account ID. Once you have the account ID defined correctly, you should be able to fetch relevant data from that account. Lastly, please ensure that you use your AdWords client account ID (and not the manager account ID) as the clientCustomerId when trying to fetch campaings related information for an account.