Alef is the first letter of the Alefbet.
For this letter, imagine a headless man. Ok, a little gruesome, but imagine it
anyways. Here's what he'd look like:

So, what does
sound like? Nothing.
Hence the headless guy. Like a man without a head,
doesn't make a sound by itself.
It doesn't sound like anything, in fact, unless it has a vowel sign under it. So now you're thinking, "What about the vowels already? Show me the vowels!"
Right. So on to your first vowel, called Patach.