Here are some things you should check:
First, navigate to your text formats: Administration » Configuration » Content authoring » Text formats and ensure the roles are configured correctly.
- Add roles you want to use wysiwyg to Filtered HTML and Full HTML (unless you've created a new text format for wysywyg, as suggested in the tutorial linked to below).
Then, navigate to your ckeditor profiles: Home » Administration » Configuration » Content authoring » CKeditor
Go to the profiles, and verify that the text formats for the profile are set, and the editor appearance is set properly.
- Under Basic Setup, check the text formats that apply
- Under Editor Appearance, set default state to enabled, and show the toggle.
Then make sure that your content type is by default set to one of the text formats configured for wysywyg. Navigate to Administration » Structure » Content types, select your content and click manage fields and edit on the fields you're having problems with. Make sure that the preset text format for that text field is set to to one of the formats configured for wysywyg (e.g. Filtered HTML if you haven't changed this).
If none of these help, please add more detail to your question. It is not very clear at the moment what exactly it is that does not work.
PS: For a secure use of WYSYWYG, I recommend using a custom text format filtered with the WYSIWYG Filter. How you do this is described in this tutorial. However, first get it working, then start tweaking to make it secure.