The Alef-Bet has 22 letters, all 'fellow' vowels with their own names. And 5 so-called final letters (sofit), but they are letters from these 22. For example, the 'a' is not just the 'a', but the Alef.
Furthermore, Hebrew is a figurative language in which each letter forms its own image. For example, the Alef a bull's head and stands for a prince, leader, head. But each letter also has a numerical value and the Alef has the value one/1. Thereby the Alef stands for the first, leader, foremost and is a reference to the First, the Eternal.
With the numerical value, letters and words sometimes take on deeper meanings, this is called Gematria. For example, the Alef (the word itself) - אלף - has numerical value 111. These are the first of the units, the first of the tens and the first of the hundreds.
So you can see that the various meanings are connected in a deep way.