Go to RDS, then click on Degree->Academic Progress-> scroll to the bottom and copy and paste your credit points and credit counted in the input field. If you want to check mannually without adding any previous history or you are fresher set 0 and press the calculate current cgpa button and add course in expected CGPA section.
Step 2: Expected CGPA Calculation
Add your courses and expected grades to calculate your projected CGPA. If course is retake, select retake and enter previous grade. Name is not mandatory, you can add for better organization.