Add fire soundpoint from Audio/Visuals - Audio, Soundpoints, Fire Noise.
To create a script linked to the soundpoint go into the Scripting part. Add a Trigger box around the soundpoint.
Add a scipt.
Link the trigger box to the script.
In the script properties, add spawn object.
Select the soundpoint and add it to the script.
Go into Explore (or Play) - when you walk into the area where you put the trigger box, if you are near enough the soundpoint should play.
Or. Use a fire that already makes a noise like the crackling of pig skin on a BBQ.