tommyboyrn
First off when you get your unit you will want to enroll in Humminbird's Select program, it will extend your warranty 1 year for free.
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http://www.humminbirdselect.com/ <---
As Chuck stated, you should start with the default settings and learn from there. You should also go to Doug Vahrenberg's site to view his 9 part seminar (towards the bottom), plus a number of good videos. This should get you started understanding how the different setting work.
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http://www.dougvahrenberg.com/Videos.html <---
I use a 4 GB Sandisk Extreme III card, there are a lot of good cards available, start with making short recordings less then an hour it will be easier to view your recordings on Hummviewer or other programs.
You will also need a USB card adapter for your computer to download recordings.
Depending on how you use your recording you may want a larger card, to date I have never come close to filling my card.
I also have the smallest card I could find which is used just for updates.
Although some reformat their cards, I have not found this to be necessary, After transferring the data I erase the old data.
Also, you should erase the old updates before uploading new updates, so that your unit will update the latest program.
As far as lake maps you may want to start with the unit map then progress to either a Navionics or a LakeMaster card. They are not cheap but have benefits showing finer detail on the lakes. Make sure that the map program you decide to purchase have the lakes you want. Also, spend some time looking at the detail of the different offerings of each map program.
George