you still need to configure https for your webserver, if I try to access the page through https://www.baltimorepolicemuseum.org/portal/index.php/en/ it just throws an error:
Most likely you can use your provider's console to generate a let's encrypt free SSL certificate ; or ask their support how to do it.
After that's done, you want to update Joomla's global configuration option; in the Global Configuratioon -> Server page the 4th item is force HTTPS => set to "Entire Site".
Additionally, you may want to use .htaccess file to get rid of index.php/ in your url. My free extension Little Helper will do that for you, or you can of course use ftp or any other suitable means to achieve that.
Do let me know once you get the certificate installed if everything works or I can assist you further.
Have a nice weekend,