Your site admin should have created a blog (a publication area) for you before you can log in on BHV (or any other wordpress blogging site) to add/change an article (or a blog or a post)
To log in your blog for the PR area.
First click on the “Changzhu yuandi”
Choose your own blog
click on the log in link on right bottom of the page
Open up the log in page and enter your username and password