From your dashboard, tap the magnifying glass icon in the top right corner. You'll then be able to search for the security you're interested in (you can search by company name or symbol). As long as the security is listed on one of our supported exchanges, it should appear in the search. Once you find the security, tap it to select and you'll be brought to a details and information page.
If you're not seeing the stock you're looking for, check out this article for more information!