When it's an article, it's colloquially pronounced ha (or a, because some speakers don't exaggerate the ה. but it's the same ה). Always ha (or a). In formal speech or writing, it is sometimes pronounced he. But as a beginner - ignore this formal stuff, it's always "ha" for you. After understanding how Hebrew works, you can learn the rules of ה as an article (for reading the bible, being a radio broadcaster, being a grammar teacher, or just to know). ו as "and" also has more forms, used in formal speech - u and va - but in every day speech it's ve. I didn't know about the existance of these formal forms until I was like, 10 years old - because no one talks like this. And I still know only some of their rules. So - לאט לאט - for you ה as an article is always ha.
Questions about two letters: כ seems to be pronounced the same as ח ב seems to be like the consonant "b" or "v" both.
Just thought I would clarify if this is the case and if so, is it possible to just pronounce the first always as "k" in king and the second as "b"? Or would that be incorrect?
To answer your question, no, you should not always pronounce those letters "k" and "b".
In modern Hebrew, there are pairs of letters that look the same except that one letter in each pair has a dot*. This causes the sound of the letter to change: The letter ב: with a dot it's bet ("b") and without a dot it's vet ("v"). The letter כ: with a dot it's kaf ("k") and without a dot it's khaf ("kh"). The letter פ: with a dot it's pay ("p") and without a dot it's fay ("f").
There's also ש: when the dot is on the upper right it's shin ("sh") and upper left is sin ("s").
I think that as you become familiar with words and memorize them, you just know which sound/letter it's supposed to be when no vowels/dots are written in.
*I learned this 35-ish years ago as a kid, so I apologize for the potentially child-like explanation.
Please don't apologize... and thank you for the great explanation! Actually I learned this some time ago but it vanished with time.
Is Duolingo using the dots though? Because I am definitely seeing כ without any dots here? I really hope I'm wrong, because that would make things confusing.