This is a good step-by-step guide to Apex for complete beginners. The instructions are very clear, so it's easy to follow.
There are two criticisms - one is that the screenshots are quite small, so make for some eyestrain after a while.
More importantly, it's aimed at v3 of Apex, so following it in v4.1 can sometimes be confusing as there's been a fair amount of movement in menu structure and navigation. Mostly the changes are easily spotted, but in some cases it's quite hard to work out what the modern equivalent should be. And of course, any recent improvements will not be covered.
So, it's useful, but an updated version would be far more so.