You can enter the correct XPath into the text box of the Single element(See the screenshot below).
1. Select the Loop Item/Cycle Pages box in the workflow
2. Select Single element for the Loop mode
3. Enter a correct XPath to find the Next Page element
4. Click Save
5. Check the workflow and see if it can keep clicking the Next Page button
No Next Page link at the bottom of the web page?
If you need to click the page number to scrape multiple web pages, it's fine to use "following-sibling::" to write the XPath for finding the page next to the current page. Just enter the correct XPath into the text box of the Single element.