Nice choice with the Aeon LE v4! I don't have it, but I have its twin, the Dominix LE v4, and it's one of the most comfortable hilts I own. Lots of good places to grip it, and the size and weight are very nice. I think that the SY LED and illuminated yellow button will go really well with the gold accents on the Aeon LE v4.
In order to charge your lightsaber, you will need to unscrew the pommel at the non-blade end of the lightsaber and slide out the battery pack with speaker. I usually have to shake the hilt a little bit for it to come out. Pop out the trustfire batteries, and place them in the charger that you hopefully ordered with your saber (it's one of the options you choose while ordering your saber--it's default that it comes with a charger unless if you specify otherwise).
In order to change soundfonts on your v3 saber, slide the battery pack out of the saber. I don't have any v3 soundboards (just v4), but I'm sure the next process is just the same as with the v4s. The soundboard is attached to the speaker/battery pack, and has a USB plug-in. Connect the USB to your computer (make sure you have downloaded the Obsidian Launcher from Ultrasaber's website first), and start playing around with it.
Here's a thread about other soundfonts you can download (it's the Obsidian Sound Fonts Board--a child board underneath "The Obsidian Order" Board):
http://www.saberforum.com/index.php?board=36.0Have fun! Congrats on your new saber!