Firefox download page shows as installed on Samsung J3 but cannot be found on phone...how to make default?

New Samsung J3 phone, has Samsung Internet as default browser. Chrome is also installed. Unchecked both from default status. Downloaded Firefox Android from webpage, page says "Installed" but there is no click-to-open link, and app search on phone does not show Firefox. Attempted reinstall, but web page says already installed. How to fix?