I received some Lily bulbs free with some other plants I bought, and I'd like to know how is the best way to store them until I plant them in autumn
Plant them now is the best advice I can give. However you store bulbs, they deteriorate when not in the soil. Plant in pots if the area you want them in isn't ready yet.
Plant them now, in pots if your garden is not very sheltered. They may well grow and produce flowers before autumn is over and they will be safe from dehydration and deterioration.
Thanks for the advice, much appreciated