So, what you should be wondering first is, wait - isn't that Alef?
Yep. As I said before, Alef doesn't sound like anything without a vowel stuck on it somewhere. Similarly, the vowels need to be stuck on some kind of letter - most of them never appear on their own. So I'm using Alef here. Yes, that little line under Alef is a vowel.

Pronounce Patach

אַ (audio)

This vowel sounds somewhere between the A in father and the A in hat. So sounds a lot like the "ah" sound you make when you open your mouth at the doctor's.

Remembering Patach

How do you remember this one? Well, the best I could come up with is "ant." Imagine that the line under is a little ant. And the first sound in ANT is A. Does that work for you? I hope so! Here's an example of what you could picture:

So, is that firmly entrenched in your psyche? Great!

Now you're reading vowels already, so let's get ourselves another consonant, the next letter in the Alefbet: Bet! You ready?