The recommended order of courses to prepare for the DP-203: Data Engineering on Microsoft Azure certification is as follows

Building an Azure Data Engineer Foundation
Data Ingestion and Preparation
Processing in Azure Using Batch Solutions
Processing in Azure Using Streaming Solutions
Secure, Monitor, and Optimize Data Storage and Processing

Finally, use the practice exams to test your understanding for the exam.

In this course, DP-203: Secure, Monitor, and Optimize Data Storage and Processing, you’ll learn the necessary skills to excel in each aspect mentioned in the title. First, you’ll explore secure options for data storage. Next, you’ll discover what monitoring capabilities are available for your different data services. Finally, you’ll learn how to optimize your data estate to get the most out of your data. When you’re finished with this course, you’ll have the skills and knowledge of securing, monitoring, and optimizing data storage and processing needed to be an effective data professional.