What should I learn for automation?
If you have programming knowlege , you an start with Selenium Test Automation for Web Application testing. However there are large number of tools there to help in Web or Mobile Automation using Record and Playback. Before start with tools, make sure that you understand the application , need of automation and range of tools fit for your requirement.
!!! Practice, practise, practise: Continue to practise and learn new implementation and optimization techniques.