To update your statement, sign in and click 'My profile' followed by 'About me' in the left hand menu. Scroll down to the box that says 'Work summary' and type your statement in here or copy and paste from MS Word, Notepad or something similar.
You can apply simple formatting such as bold, italic, bullet points and links. To add a paragraph break between CV information, click the carriage return/enter key on your keyboard. To add a single line break, hold down the shift key while clicking the carriage return/enter key.
Once you've finished editing your statement click 'Publish changes' at the bottom of the page and this will make the changed live on your profile.