It doesn't really matter. According to the response of the on-site examiner, the score and signature will be uploaded to the system after the signature is confirmed. Whether you save or not, it doesn't matter much whether you click OK.
However, if you are so excited that you forget to click OK at the end of your signature, you need to sign up or retake the exam later according to the normal procedure. According to Article 46 of the Regulations on the Application and Use of Motor Vehicle Driving License, the examination records of all subjects shall be signed by the applicant and the examiner. Unsigned motor vehicle driver's license shall not be issued.
Of course, this statement is not absolute, it depends on your luck. Because there are some examination rooms now, in order to prevent candidates from forgetting to click the confirm option, the system will automatically confirm the signature. I suggest that you can ask the driving school about your exam results in subject one afterwards. If you are lucky, you will get a result, indicating that the examination system has been automatically confirmed. If you don't get the result, you will have to make a new appointment for the exam.
Matters needing attention in subject one exam
1. It is recommended to arrive at the examination room half an hour before the exam. Because many people come to take the exam for the first time, they will inevitably feel nervous in the face of the examination room. Arriving at the examination room in advance can familiarize you with the layout of the examination room and relieve your nervousness. Before the course begins, the examiner will explain the precautions to the students in advance, so try to get to the examination room as early as possible.
2. After allocating the seat number, find your own position. Especially before the examiner in the examination room speaks, don't click "OK" on the screen. Just sit in your seat and do nothing. If you don't understand, you can ask the invigilator or team leader.
Don't cover your face with a hat or hands during the exam. Because there is a camera on the computer during the exam to monitor the answer status of the exam in real time and judge whether there is cheating, and this monitoring will be uploaded together with the test questions as one of the basis for issuing your driver's license at last. So don't cover your face if you have nothing to do.