At least a year, although you will eat it all up long before then!
I recommend Marguerite Patten's book, which is the absolute gold standard for jam & preserves. Link here Recipes by the WI are good too. It is really vital to follow a good reliable recipe and sterilise the jars properly (not difficult, you just need to be meticulous.
Labels - try Martha Stewart's website for printable templates for all sorts of things - bet there is something suitable.