Once you login, click on your username at the top

You'll be taken to a 'Bio' page where you can place your contextual backlink using the format as shown in the pic. Don't forget to hit the 'Save Changes' button.

Visit the 'About' tab and enter your URL in the "Web Address" field and hit the 'Save Changes' button.

Now visit the URL - https://www.avitop.com/cs/members/YOURUSERNAME.aspx (Replace USERNAME with your username in the URL) to check the backlink.

Voila! Both your backlinks are ready.