Thanks Alex. Yes, actually the answer is in the tips that your pasted at above. But to be honestly, it is not good tutorial enough, post my experience for those people who has existed SSL, please refer the installation as following:
0. In my version, it is called 'SSL Certificates'. Click it.
1. select the radio button: 'Paste a pre-generated certificate and key'
2. Paste all content of xxx.key at the box of 'Paste a pre-generated certificate and key' as private key that generated with csr.
3. Paste all content of xxx.crt after the key at the same box issued by certificated authority organization.
4. save it.
5 If you have bundle cert file, past all content of bundle crt file at the box that after click the link: 'Click Here to paste a CA Root Certificate', then save it.
6. don't forget enable SSL, and also pick up the option: 'Use a symbolic link from private_html to public_html - allows for same data in http and https', if you want to share same content for both private and public. Otherwise, pick up the option: Use a directory named private_html
