Maintenace on a Icon is pretty simple. Remove the bolt and hammer, notice how they link together and how the mainspring, spring strut and bumper line up. Swab/ clean the top and lower tubes and the feedneck area. Apply a small amount of paintball oil or grease to the hammer and to the bolt orings.
That's about it, besides keeping the battery fresh. Paintballsolutions.com has online manuals if you need further help.