Heading of your post says you wanted to prepare "HR Business Plan" whereas in the body of the post you have written you wanted to make a business plan. Therefore, what exactly is your requirement?
By the way, there is nothing like "HR Business Plan". You may make a note of it.
Earlier there was discussion on similar subject. I have given components of the business plan. Click the following link to refer it:
10th February 2017 From India, Bangalore