1. Step 1: Open the browser, enter the main interface, select the "Menu" button in the upper right corner of the toolbar, and then select the "Add-ons" option, as shown in the figure below, and then proceed to the next step.
2. Secondly, after completing the above steps, enter the component addition page. Click the "Plug-in" option in the left toolbar, as shown in the figure below, and then go to the next step.
3. After completing the above steps, enter "epub" in the search box in the upper right corner of the plug-in page to search, as shown in the figure below, and then go to the next step.
4. Then, after completing the above steps, check the first search result, click the "Install" button on the right, as shown in the figure below, and then go to the next step.
5. Then complete the above steps. After the installation is completed, a restart prompt will appear. Click "Restart immediately", as shown in the figure below, and then proceed to the next step.
6. Then, restart the browser after completing the above steps. Click the "Book" icon in the upper right corner, as shown in the figure below, and then go to the next step.
7. Then, after completing the above steps, click the "Sync" button in the upper left corner, as shown in the figure below, and then proceed to the next step.
8. Then, after completing the above steps, click the "Import" option on the left, select a folder containing epub files, and then confirm that you will see the epub files of the imported pages in this folder, as shown in the figure below, and then proceed to the next step.
9. Then, after completing the above steps, return to the book browser page, click "My stacks" on the left, and you will find the newly imported books appear in the book catalog, as shown in the figure below, and then go to the next step.
10. Finally, after completing the above steps, click any title to browse the specific contents in the epub file. On the left is the table of contents, and on the right is the text. The completed renderings are shown in the following figure. In this way, the problem is solved.