I would, but i just don't have time. I think all you have to do is use ambient_generic, give it a name, put the path as your custom sound, and tick the "don't loop" and "start silent" flags. Then make a trigger or something with the target as the name of the ambient_generic. The custom sound should be in your "sounds" folder, too. If you want it to be a sound that just loops in the background near a point, don't give it a name and untick the "don't loop" and "start silent" flags.
When you upload a map with custom sounds to the vault, be sure to include those sounds. I hoped this helped.