Login: Go to http://www.yoursite.com/wp-login.php and enter your Username and your Password provided by the person who installed the website.
Once connected, you arrive on the Dashboard. The first thing you need to do is to access the Profile section to change your password in order to be the only one that knows it. Click on your name in top right corner > Edit My Profile, or Users > Your Profile in the left menu. Go to About Yourself section and write down the new password in the field New Password and Repeat New Password. Complete and update any other desired section in Profile, including Personal Options, Name, Contact Info and WordPress SEO settings. Click Update Profile.
Now you may want to change the general configuration in Settings section: Site Title, Tagline, E-mail Address, Membership (if you accept new members, and their role), Timezone, Date Format, Time Format, Week Starts On, and Site Language. The newest versions of WordPress are translated into 44 languages, with an ongoing work to add new languages.
Now is the time to add content or edit existing content.
Add/edit pages: Select a page to edit from Pages > All Pages, or add a new one from Pages > Add New. The first field you need to fill is the title of the page. Then use the visual editor to enter the content of your page. All the other fields are optional but it is recommended to use it for a better navigation, interactivity and optimization for search engines. You can click the Preview Changes button in the top right corner to give you an overview of the scale appearance of your page on your website. Click Update or Publish if it was an update or a new page.
Add/edit posts: Add or edit posts works the same way as for pages, but there has, however, some additional optional information you must enter. You can change the layout and format of your post. You must also assign at least a category of the post. On the right side under the Categories box, you can add tags to your posts. Your visitors will use these keywords in their search of posts. You can preview and edit your posts in the same way you would for pages. Click Update or Publish if it was an update or a new post.