Next I'll explain how to modify which instrument sets and sound effects are connected to each sequence in the sdat.
Open up info.bin in a hex editor such as MadEdit, if you are not familiar with hex editing you'll first need to learn this.
At 0x40 you'll find the main table of sequences contained in sdat, each of these offsets points to the settings for each sequence respectively.
Note that the file is written in little-endian, meaning each set of four bytes is reverse and "08 02 00 00" should be read as "00 00 02 08" therefore pointing to 0x208 in info.bin.
In this example I'll show you how to change the settings of NCS_BGM_JAZZ (One of the mini-game songs) to behave like NCS_BGM_CHIJOU (Bob-omb's Battlefield music).
Their pointers are 0x1F0 and 0x448 respectively. Let's take a look at what's at 0x448: 38 00 00 00 65 00 60 40 40 00 00 00
The first part (00 00 00 38 - little-endian, remember) is the sseq file id used, we don't need to change this.
The second part (40 60 00 65) is what we'll be copying over the same data at 0x1F4 to produce our desired result.
The last part (00 00 00 40) just marks the end of this entry.
So, now we'll go to 0x1F0 to see the NCS_BGM_JAZZ settings: 08 00 00 00 5F 00 69 40 40 00 00 00
Here we'll need to replace "5F 00 69 40" with the bytes used in NCS_BGM_CHJOU's entry, which are "65 00 60 40".
Once you've done this, you'll be able to replace NCS_BGM_JAZZ with NCS_BGM_CHIJOU and should find that it plays correctly.