If you're not sure what we mean by "Concept" or "Location" in meez, please read this article for more details.
To find the Location ID for any location in your account, go to the Concepts page on the admin side-bar. Under each of your concepts you will see a location name (left) and a location ID (right).
Please Note: Business and Premium accounts come with a single concept pre-loaded. This will be named "First Concept" by default. This concept comes with a single location, named "First Location." You will probably want to rename these on the Concept page of your account.