You have to install phpBB3 first.
Upload the phpBB3 files to the same server as SMF, but in a different folder.
Upload the three SMF convertor files to where I told you.
Using your browser, browse to the phpBB3 folder.
The install will start automatically.
Follow the instructions.
You will be asked for database information. You can use your SMF database.
When the installation is done, There will be a convert tab at the top of the page.
Click the convert tab.
There will be two convertors listed, the phpBB convertor and the SMF convertor.
Choose the SMF convertor.
Follow the instructions to finish the conversion.
You are done.
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