The specific steps are as follows:

1. First, the page number part changes to "Error! Undefined bookmark", as shown in the figure below, and then enter the next step.

2. Secondly, return to the part of the document where the content cannot be displayed correctly, click the mouse at each location where the directory needs to be defined, let the cursor stay, and then click the toolbar Click the "Insert" button on the

?, as shown in the figure below, and then proceed to the next step.

3. Then, click the "Bookmark" option under the Insert button, as shown in the figure below, and then proceed to the next step.

4. Then, enter any Chinese characters in the pop-up bookmark window, then define the bookmark name here, click Add, as shown in the figure below, and then enter the next step.

5. Then, after completing the above steps, insert bookmarks into the three directory levels, as shown in the figure below, and then proceed to the next step.

6. Then, after completing the above operations, return to the document directory, click anywhere in the directory, right-click, and then select "

Update Domain" option, as shown in the figure below, and then proceed to the next step.

7. Finally, return to the document again, and you can see that the directory is displayed normally, as shown in the figure below. In this way, the problem is solved.