On the left navigation menu, click on "Company Profile".  This will open the menu. 

Click on "Certifications" to go to the certifications section, which displays the list of the certifications you have in your profile.

To add a new certification or edit an existing certification, click on the "Edit" button. It will open up an edit pane on the right. 

Add new certification, click "Add More Certifications"

To edit a certification, click "Remove" next to the certification and then click "Add More Certifications" to add it as a new certification.