Here the things you need for this tut:
~Two copies of the rom you want to insert the music in
~Visual Boy Advance{Or any emulator to play it}
~mid2agb and Sappy{You can download this from magnius tut}
The Midi music you want to insert{You can google them}
Here goes:
Step 1
After downloading the two files{Mid2agb and Sappy}extract them{using Winrar}to one file...and open Mid2gba.
Now we will be converting the midi file you want to insert to .S file using mid2agb...
Then drag your midi to the mid2agb then it will automatically converted to .s file.
Step 2
Putting in the converted file...
First Open Sappy then open the rom you want to insert the music in.
then there will be a song tittle there,you can click it and a list of music from the original rom wil appear.
You can choose any songs there to be change but im changing the music of Pallet Town.
After you choose it,there will be a word called assemble songs there,click it.
then browse the rom you want to use and choose it..
After that on the second box{Base Destination Offset}put this in,0xEB0B20
Next is the Voicegroup,you should not care about it for now{It is for the sound of your music in the game,magnius has the tut for this}
Then click "Assemble That Ugly Thing"then wai for it to finish,there will be a text out saying you want to put the.....{for me i press yes}
After that,click play to check whether the music you inserted is there,if it is then good...and if you are lucky the song will be played in your game..
If not..sit around and listen to more steps..
Step 3
Making the music work in the game,
After you assemble the music,we will be exporting them now...
if you have closed Sappy,reopen it and open back the rom you just inserted the music in.
Now scroll down to the music you change and choose it.
then there will be a phrase there says export music{double check whether you press the coorect one}
Then there will be a bunch of uncheck boxes or a phrase with a small box beside it not tick.
Check all of them.The other box you should type in $T{reason,ask magnius}then press ok.
now the a string of number will appear on the folder of the rom you exported the music.{the number is from 0-1-2-3 and so on}
After this close Sappy then reopen it.
Now open the rom you have not inserted the song in yet{this is the reason why you need two of the same roms}
and choose the music you were changing in the previous rom which i was changing pallet town.
Now click IMPORT FILES then you will see the same string of numbers you exported{If you do not see them,you most probably open this rom from another folder,you must put the two roms together}
Check all of the string of numbers box,then put this on the box called First Track Box 0xEB0B20
Then Press ok.Now try playing on your emulator and see whether it works..
If not,redo all the steps again..