Glossary page, how to streamline (for a beginner…)

My site has been a simple ‘business card’ for years, without any additional functionality or content.
Recently, though, I’ve started growing a page of glossary terms, (Italian to English translations of legal terms), alphabetized in a list, so I’m looking for some basic guidance how to organize this growing list of terms more efficiently, e.g., a bar across the top with the letters of the alphabet, so you click on a letter to go straight to the glossary terms starting with that letter… Simple stuff, but I’m all thumbs – can anyone point me in the right direction, please?