Look on page 39 of your owner's manual for the over view of what you need to update.
You'll need to buy an AS PC2 cable to connect your fish finder to your PC.
Next, you need to register your unit with Humminbird by setting up an account and then you'll log in and download the latest version of HumminbirdPC.
Install it.
This is important! Before you connect your fish finder to the computer and attempting an update restore your unit to its factory defaults. If you don't, you run the risk of having a problem and having to send your unit to Humminbird for them to make a fix that only the factory can make. Look at page 73 of your owner's manual for instructions on how do to this. (This option is under the Setup menu tab.)
Now run HumminbirdPC and connect your unit following the instruction with the AS PC2 cable. Follow the instructions to update your unit.
Now, before doing all this, you might want to write down all the changes and settings you've made to the unit, such as depth offset, scroll speeds, etc.
Lastly, before trying to use the unit, reconnect on the boat and reset the factory defaults again.
Now you can go back and reset all your preferred settings.
You may still need to follow what the others have said about downloading the .bin file and putting it someplace where you can point to it manually.
Good luck.
Quit complaining about the color, just pull up your skirt and fish! -- snagged