As the name suggests, the About Me section allows you to tell the recruiter about yourself. Without sounding narcissistic, your goal is to convince in a few sentences that your CV matches the profile sought in the company.
To complete the About Me section, write a short blurb that highlights the qualities of your CV and elements of your profile similar to those appearing in the ad.
With this section correctly completed, the recruiter will immediately know that you are a serious candidate and will read the rest of your CV carefully.
Note: no need to go long. 5 or 6 lines are sufficient to complete the About Me section and to stand out from other applicants.