Q:
How to merge PDF files using PDF Reader Pro for Windows ?
A:

You can use PDF Reader Pro to merge your PDF documents into a new PDF file.

1. Tap Page Edit  on the sidebar.

2. Tap Merge  to combine multiple PDF files into a new PDF document, and you can also borrow individual pages from another PDF file to merge.

3. Tap + to add files you want to combine.

4. Set the page range and page size as you desire.