Tink try this link....

Download GPS coordinates

Look at the bottom of the page and download the free Easy GPS software first.

Then select the lake you want, then in the Easy Gps tool bar select send to gps

Then select your Fishfinder for the drop down list, then send to a file on your computer.
[I usually select only one lake at time and name the file with that lake name. That way I will save each lake separately when copying to a card.]

After you have the lake or lakes on your computer load them to a blank card. You should be able to insert into your unit and down load to memory.
Hope this helps.
I have Lowrance so I can't help you any further.