Just got a new navionics card for HB Helix 9 si gps. Is it just �plug and play� right out of the box, or does it need some kind of preparation?

Plug and play.

You should register it and do an update so you can have current data.
That will also start the Freshest Data subscription for a year.

I�ll try that Wayne, it also came with a memory stick. Is this for back up?

No it did not come with a memory stick.
It comes with a USB memory card reader in case your computer does not have one.

Thanks Wayne.

If it is a new card, I would also recommend making sure that the Sonar Chart layer is turned on. To do this, hit menu twice, scroll over to chart, then down to chart select. The default normally shows it in Auto, but toggle to the right until you see either "Left FishNChip Card" or "Right FishNChip Card", depending on what card slot the card is inserted in. Now exit and go fishing. This is a one time setup and some Humminbird units will automatically turn it on and other wont, but it will allow you to get the most detail out of your card. Good Luck!!