Yep, you'll need to use Translhextion or some other hex editor. There's a good hex editing tutorial on this site, which is right here
. That will pretty much clear up a lot of your questions on how to make hex edits, but I'll go ahead and list the steps on how to make this particular edit:
First, make sure to back up your ROM before editing. It's possible that you could screw up something important in the ROM, so this is just to be safe.
Then you'll need to open up Translhextion and open your ROM. From here press Ctrl+G (or go to Offset > Jump To...) and type "x01924" without quotes.
This should take you directly to that offset which should have a value of 13 at the moment. From there, change the 13 to any value you want by typing a letter or number while the blinking cursor is highlighted over it. For example, changing the 13 to 02 will change the music in the intro level to "Here We Go!" as heard in level 105.
After that, save the edits you made and test your ROM to make sure it worked!