You sound like you are completely overwhelmed, so try to focus on the basics first and start simple.
By planting in the garden I assume you mean in flower beds. For this you want a range of hardy perennials, which are there all the time, then you can fill in the gaps with annuals. Some of these will go on into late autumn, keep deadheading them. When they die get rid, if they are perennials they won't die (hopefully). Some perennials regrow from new each year, you will often see new shoots popping up around the base of the plant from the autumn, but wait to cut back the dead stuff until spring.
Obvious hardy perennials to look out for, and that are easy, are things like roses, peonies, hardy geraniums, sedums, oriental poppies, geums, verbena, fuchsia, hypericum. Websites like Farmer Gracy and Crocus have good advice sections.
Then some hardy annuals will self seed and pop up each year like Nigella, Calendula, foxgloves. I always grow Cosmos from seed as they are dead easy to grow, and fill up gaps quickly and abundantly.
I would forget tulips for this year, plant them in the autumn for next spring. I treat tulips as annuals.
The tip for the Hessayon book is a good call. I have so many beautiful gardening books, but i go back to the no nonsense advice time and again. His book on the easy care garden is also good.
As a more general introduction I always recommend Gardening in Pyjamas by Helen Yemm.