just an FYI, if you are at a computer, you can set this all up on there. Just open up Internet Explorer and go to Bing.com. Log in with your Microsoft Account (Ensure that you've also signed-up for the Bing Rewards program also....not required, but might as well so that you earn points to buy stuff).
Ensure that in Bing "Settings" and then on "Personalization", that it is set to use Cortana data or whatever it is called "Other Cortana data".
You can add interests there and check your search history, etc. it is a bit easier than doing it on a cell phone, in my opinion. I have not checked or tried to tell Cortana to "add an interest" or something along the lines of that..but that might work also. Either way, just know that you can open up Bing.com and log in with your Microsoft Account on a larger screen such as a computer, and access much of the stuff that Cortana uses to give you updates.