Depending on what you want to do, a macro recorder
might also get the job done.
This will replay the actions you recorded before, but lacks evaluating conditions, like for example AutoHotKey can.
AutoHotKEy is a good candidate for automation. It has a somewhat relaxt syntax and can do about anything (*).
AutoIT is much more strict; more for real developers.
No experience with other tools.
Best way to learn:
Find something you want to automate, decide which tool would fit best and ... just start!
There is always a forum to help you out.
And even if it fails, you learned a lot for your next project.
Sidenote: after 5 days of usage, AHK seemed awesome. But after 5 weeks, that "relaxt" way of handling things started to work against me:
you're never sure if you had the right syntax, so you have to "try & error". Maybe things will get better in the sixth week
Most irritating till now: I couldn't get "function a" to work, until I read the help describing "function b": mutual exclusive with "function a". No mention of that in the help of function a ...