If you go to your profile, you'll see a link at the top of the page for 'Add'. When you hover on that, you'll see the link for 'DNA test information'. That will take you to the page where you can enter your ancestryDNA information.
I recommend you upload your ancestry raw data to Gedmatch.com. It's free to do so. People from all three testing sites (23andMe, FTDNA, ancestry) can upload there, so you'll get more matches. Also, you'll be able to see how much DNA you share with your matches, as well as the chromosome segments you're sharing with them. This is something you can't do with ancestry. With that data, you can determine triangulated groups to work on mapping your chromosomes. If you decide to upload to Gedmatch, you may want to create a new email account specifically for DNA matches (perhaps through gmail). That will allow you to keep your 'personal' email account private.
