Welcome to the forum Malcolm. If you have no experience of hiking I assume you do not possess walking boots/shoes. I suggest that you trawl through the relevant sections here on equipment so that you can identify what would suit your needs and make sure your footwear is well broken in (although my Salamon boots were great from the start) before you start walking. Some UK outdoor clothing stores allow you 'test drive' boots and backpacks for up to a month before returning them if unsuitable, just as long as they have not been outdoors. As you are planning to walk in May you probably can do without a sleeping bag, which will cut down weight in your backpack, and yo can manage with a liner instead. As Wayfarer said, most people use the
Brierley guide. I did and found it most useful for my first Camino last year. Start the process of toughening up your feet and building strength in your legs by scheduling more walking into your daily life now, as the first stage of the
Camino Frances will make real demands on your stamina. But you are young - I am in my late 60s - so you will be fine and have the journey of a lifetime. Buen Camino!