There is no comparability between oral English test and CET-4 and CET-6 because they are completely different test forms. The oral test is divided into two parts: oral English and interpretation. I won't go into details. You can go to official website or the website of "Translation Music Interpretation School". Are introduced in detail.
The written test of advanced interpretation is equivalent to TEM-8 (even worse than TEM-8 to some extent), and the passing rate of oral test is very low. If you pass the interpretation exam, there is no problem. Come on, simultaneous interpretation!
As for preparing for the exam, since there is no foundation, I recommend you sign up for a class, starting with intermediate interpretation. I don't know where you are from. If you are from Jiangsu, you'd better go to Suzhou Yigele Interpretation School, which is the most professional interpretation training institution in the Yangtze River Delta region.
The code word is difficult, I hope my answer will help you!