Obscurelighty allows content editing directly from the website. There is not "administration" section outside your website.
To activate the editing system, you will need to login.
Depending on your configuration and your hosting, several solutions would be proposed. The first and classical method is the "form".

"Edit" button

Once logged into the site, an "edit" button will appear on your pages at all editable areas.
When your mouse would be hover an editable area, the background color of the area would change (with a little outline too) which would indicate the size of the area. The pencil icon will be highlited.

Thanks to this little pencil icon, you can edit the content of the selected area.
A window within your website will open. If the content is in HTML format, a WYSIWYG edit will be used.

You can always switch to the other editor to edit the HTML code directly.

The "Preview" button allows you to send your data to the server and directly visualize the final result.
Generating the preview will also create a backup on the server. As long as the content is not validated or deleted, reopening the editor would reload the same backuped content.
Preview allows you to verify that the rendering, the result is what you want to have. The "validate" button would be displayed in order to finalize your modifications.