I might give this a try. So basically, the only restriction is that it has to be orchestral and war-like? Those are very loose requirements, so you may not like the result. Oh well, I'll see what I can do.
Drag and drop commands could help you out here more than you think.
firstly, MAKE SURE THE EXPLOSION SPRITE IS ON CENTER (common mistake if this is the problem) The simplest way for the bomb to create the explosion is using the create object explosion (relative to) bomb's location, the next case is that the bomb does not stop traveling and does not create the explosion in the right position, make it destroy itself on collision w/ the enemy. I'm assuming you made the DnD happen, make sure these happen.
The explosion destroying itself should be done more simply
Within the Other Tab in the Event menu, there is the term, Animation end (also assuming that the explosion should only happen once. select that then select Destroy instance and DnD, that simple, no need for alarms.
Make sure all instances apply to selves and the bombs should work. I don't know much, I'm only going to help with what I learned from DnD Trial and Error.
Description of the sound (Instrumental Music)
In case of music, the style (Patriotic, Militaristic ?)
Length of the sound effect or music (Don't care, Go nuts)
The file size limit (if any) (As much as you need)
In case of wave files, quality (11 Khz, 22 Khz, 44 Khz, mono / stereo) (See Requirement #3)
File format (WAV, MP3, Midi, MOD, et cetera) (MP3)
If available, a link to your game (WIP, no link yet, the game isn't even playable as of now)