There are 3 ways for you to access the PDF merger in PDF Reader
Merge Multiple PDFs into One (Through Mac's Finder)
1. Launch PDF Reader
2. Switch to the “Management” mode and click on the “Merge PDFs” entrance under the office toolset section
3. Choose 2 or more PDF file from Mac's Finder, and then you will be brought to the settings window
4. You can drag the files to rearrange the file order for merging
5. Then click the "Merge" button and choose the destination folder
6. The output file will be stored in the folder
From the Tool menu (Append files to the current PDF)
1. Open one PDF in PDF Reader
2. Click on the "Tool" menu from the top menu bar and select the "Merge" option
3. You will be directed to the settings window. Click "Add Files" to select files that you wan to append to the current PDF
4. Then click "Append" and merge PDFs
Using the Page Editor (Append files to the current PDF)
1. Open a PDF document in PDF Reader.
2. Click on the "Page Edit" icon on the top toolbar to see a grid of all pages in the current PDF.
3. Select the "Append" option.
4. Click the "Add Files" button and select files that you want to append to the PDF
5. Press "Append" to start merging