Start with the job in front of you
Merging is fast; discovering that an appendix came before a signature page is not. Gather files in a folder and decide the intended order before dropping them into a merge tool.
A short test is usually faster than trying to fix a large final file after the fact. Keep the original nearby, name the exported version clearly, and change one setting at a time when the result matters.
Use a small, repeatable routine
Name source files with a number when order matters, then scan the first and last page of each document after merging. This takes less time than trying to explain a mixed-up attachment.
The useful part of a browser tool is not simply getting an output. It is being able to reproduce the same result tomorrow, explain what changed, and notice when an input or assumption has changed.
Do one last check before sharing
Open the merged file and jump to the boundaries between source documents. That is where missing pages and repeated covers usually show up.
If the result will be published, sent to a client, or used to make a decision, compare it with the source rather than trusting a filename or a successful download message.
Practical checklist
- Keep the original input until the output is checked.
- Test the workflow on a small sample first.
- Use clear names for exported versions.
- Review the result in the app where it will actually be used.
- Record important settings or assumptions.