The second layer is optional. Both the written test and the computer test can be passed. The exam includes a written test and a computer test, which you must pass. However, if you only pass one course, you can keep your utility until the next exam. In other words, if you pass the computer test, you can skip the written test next time. The simplest level 2 is VFP, which is relatively basic. For certificates, you can choose VFP.
Level three. I'm not sure. I haven't even taken the exam yet! !
I hope it helps you.