Installing a new battery is very simple. However, for the uninitiated, here is the procedure.
Fist, make certain to get a properly sized replacement battery. KTM offers more than one size of battery box and now might be the time upgrade to a larger battery box and battery! See article: Battery Box Replacement.
Comparison between two sizes of batteries.
Remove the foil air seal.
Invert the acid container and press down into the battery to pierce the seal.
Wait for the acid to transfer into the battery.
If needed, pierce the acid container with a pin to allow all of the acid to drain out.
Remove the acid container when empty.
Install the battery cap.
Charge the battery. You should never use a car charger for a motorcycle battery as it provides too much curreent. The proper charging current is approximately 400 milliamps.