Linda...buy a package of sure-jell...the way to prepare juice is on a paper inside...with jelly recipes...it tella you how much juice to use, and how much sugar...the secret of good jelly is experience...being able to tell by the way ir looks , whento pour it up...and be sure to wipe the tops of your jars clean before putting lids on...and have a small pot of water on to boil...and drop the lids in a minute before sealing with them. Goodluck...nothing is better than blackberry jelly on a buttered biscuit! I put a vine out...down at my daughter's lake house. Stella