Navigate to [https://tagmanager.google.com/](https://tagmanager.google.com/)

select Data Layer Variable as the variable type.

In the Data Layer Variable Name field, enter the key exactly as it was written in the code (e.g. bookTitle, not book title.)
 In most cases you should leave the Data Layer Version set to the default value of Version 2.

In the Data Layer Variable Name field, enter the key exactly as it was written in the code (e.g. bookTitle, not book title.)

 In most cases you should leave the Data Layer Version set to the default value of Version 2.

Create a Data Layer Variable in Google Tag Manager