1. If you want to adjust the historical barrage, you must first be a member of Bili Bili, and register as a member. Otherwise, you will find that the "historical barrage" on the right side of the video is transparent and cannot be clicked, as shown below:

2. Therefore, if you want to view the historical barrage, you need to click the Login or Register button at the top of the page to log in as a member:

3. After logging in to watch the video, you will find that you can click on it to view the historical barrage:

4. Click on the historical barrage, and you can freely choose the time point and the historical barrage you want to view, as shown in the following figure:

5. This time point means that, for example, if July 1 is selected, the historical barrage shown below is the barrage content before July 1, as follows: