It would be great if someone can elaborate on the practical side(corporate use) of the technical skill and the duration to master the skill.
From India

We could tell you what we think you need to know, but at the end of the day, every organisation is different and THEY will decide what skills a HR person needs to meet the objectives of their company. So the question you should be asking yourself is what sort of organisation do I want to work for, and then go and talk to HR people in the industry sector you hope to work, and ask them the questions of what will be needed.
From Australia, Melbourne
Best wishes
From India