Playmusic (1);
But, the midifile where i put?
In the game folder, the same one where you save your rooms.
NOT in the "Compiled" folder.
How i called it?
It depends on the file extension, but you can use OGG, MP3, MIDI, WAV, MOD, XM, and S3M music files. SO, for example, you have a MIDI file you want to use for your music, name it like:
MUSIC1.MID
or if it's in MP3 format, then it'd be named MUSIC1.MP3
you can have a mix of different formats, and so it might look like
MUSIC1.MID
MUSIC2.WAV
MUSIC3.MP3
etc...
But when you tell AGS to play a MUSIC file, you just supply the music file number accordingly.
So, example in a script, you might use:
PlayMusic(1);
Or simply from the interface, for example, upon entering a room, from the room editor, and from the "Interaction" ( i ) button towards the top of the room editor, click and you will be presented with a choice of option. You can choose something such as: Player Enters Screen (before fadein), right-click and select "New Action", then choose "Game - Play Music" then put in the music file number ( example: the CHANGE button, then enter 1), then OK. there you have it. when player enters that room, it should start playing your selected music file. ;D
All of this is, of course, in the AGS Manual. Did you try reading through it, TAFFURI?