[Ironboy]

pawn Код:

new message[] = "message\n messgae2\n message3...";
    new message2[] = "\nmessage4\n message5 and so on..";
    new string[256];//you can change the string value according to the length of the line/message
    format(string, sizeof(string),"%s %s",message,message2);
    ShowPlayerDialog(playerid, 19343, DIALOG_STYLE_MSGBOX,"Test",string,"Select","Cancel");