Or another method
You need a newspaper, a fridge, salt and pillys
Buy fresh pillys/sardines from your local seafood shop. Try the Chinese/Vietnamese one they're better and cheaper .
Open your newspaper in the middle, dispose of any glossy junk and add a layer of salt on one side,Add a layer of pillys, add a layer of salt. Fold the other side of the paper over them.Put em in the fridge. After 12-24 hours turn the whole shebang over. The newspaper soaks up all the water that the salt draws out.
After 24-36 hours you now have fairly dry tough flavoursome fishy treats. Ready for use or the freezer.
Once again don't try this in the wrong fridge.
EDIT, better detail