Following these steps will allow your environment to be provisioned on time:

Step 1 - On the contract start date, provision the system via SAP for Me.
Step 2 - Activate your Account Owner role following the instructions provided in the activation e-mail (link valid for 30 days). For more info, consult Activate your Account Owner role.
Step 3 - Follow this guide to activate your SAP Engagement Cloud add-on.
Step 4 - After completing the previous steps, check the following guide for more information: Getting started with SAP Engagement Cloud.
By default, you are entitled to one production tenant unless otherwise stated in your contract.