I have an IP. To be honest I wouldn't bother with a cookery book for the time being, as there are so many recipes online. Just google, for example, 'beef casserole instant pot', 'rice pudding instant pot' and so on, and you'll find loads of recipes. One good blog to follow is Feisty Tapas.
Also, if you're on facebook, join the Instant Pot UK Community - they are so very helpful, with loads of tips and information as well as masses of recipes. They have a 'pinned post' at the top of their page which will give you all the 'Dos and Don'ts' - really an essential read for anyone new to the Instant Pot.
Pinterest is another excellent source of recipes.