SAP E-Recruitment Implementation Sequence

Dear Experts,

Now I am starting E-Recruitment Implementation in the landscape. I have few doubts in starting phase to proceed further.

After my search i came to know that, having Standalone E-Recruitment system is the best option for setting up E-Recruitment System.

Now i want to know that What are all the list of Software needs to be install to setup a complete E-Recruitment Landscape.

Below are my understanding on the same, please correct me if i am wrong.

1. Install SAP Netweaver ABAP with addon E-Recruitment package.

2. Install SAP Netweaver Java with E-Recruitment BP's

3. Install Trex search engine  standalone.

4. Integrate E-Recruitment to ECC HR System

Thanks

A Sharif