The steps make reasonably clear which line to add the "/safeboot:minimal /sos /bootlog" text. Following the steps, beginning with 4, you're told to locate a particular line, copy and paste that line, change the description of that line, and then add some text to the end. Clearly, the addition is to the newly copied and pasted line.

Granted, the steps would be clearer if written like this:

4. Locate the line that includes the /fastdetect switch. It should look something like this:

  multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" ... /fastdetect ...

5. Copy and paste that line so you can make changes to the copy.

6. Change the description between the quotation marks (e.g., "Windows XP Professional") to "Safe Mode" or something similar.

7. Append "/safeboot:minimal /sos /bootlog" to the line. The result should look something like this:

  multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Safe Mode" ... /fastdetect ... /safeboot:minimal /sos /bootlog